Your skin keeps things out. That is the whole problem.

The outer layer of your skin is a barrier. Its job is to keep things out. It is the reason you can swim without absorbing the pool.

Which means it does not care what your serum cost. An expensive active and a cheap one meet the same closed door.

So most of what you pat on stays on top. It dries. It wipes off. It ends up on your pillow.

This is not a flaw in one product. It is the condition every bottle on your shelf works under. Most of them never mention it.

The stratum corneum is not a defect to be defeated. It is the reason a human body holds roughly sixty percent water while sitting in dry air, and the reason a swimmer does not absorb a pool. Dead corneocytes are packed flat in a continuous lipid matrix, and that arrangement is tuned for one job: letting almost nothing through in either direction.

Everything difficult about topical skincare follows from that. A molecule does not fail to cross because the formula was cheap. It fails because the tissue is doing exactly what kept the organism alive. Any honest account of a serum has to start by admitting the barrier is winning by design, and that a better formula competes for the same three doors as a worse one.

There are only three ways across that outer layer. Every serum ever made is competing for them.

One winds between the cells, through a matrix of fat. It is long, and it is fussy about what it lets through.

One goes straight through the cells. That means crossing water, then fat, then water again. Very few molecules manage all of it.

One uses hair follicles and sweat ducts. That route is fast, and it is almost nowhere.

Reformulating changes how well a molecule handles those three. It never adds a fourth.

Absorption does not push product in. It opens temporary channels through that outer layer. The formula then travels a road that is briefly open, instead of arguing with a closed one.

The needle is 8 µm. Depth is a separate control, from 0.5 to 1.5 mm, and the collar has no clicks or stops. Which means you set it where you want it and nowhere else.

Intensity is a third control, with six settings. Depth is how far. Intensity is how hard. You never adjust both with one dial.

8 µm is finer than molding holds, so the array is not molded. It is made the way semiconductor parts are made, and the device page prints the process, the tip angles and the surface.

Precision about category matters more than enthusiasm. The Tap Pen is a cosmetic device. It is not a prescription treatment, and it is not a clinical procedure performed by a practitioner.

It is also not an injection. An injection deposits a measured volume into tissue at a known depth. This opens temporary channels through the outer layer and lets an ampoule meet them. Those are different mechanisms with different consequences, and conflating them would be the easiest way to overstate what the device does.

Nor is it a dermaroller. A roller enters at an angle as the drum turns, so entry and exit are not vertical, and the needle is typically an order of magnitude wider. The comparison table above puts the published figures side by side rather than describing the difference in adjectives.

The opening is temporary. Skin begins closing it immediately, and the sequence is the ordinary wound response operating at a very small scale: the channel narrows, the surface re-seals, and the outer layer returns to doing its job.

re:tones has not measured how long that takes for this device, and no figure for it appears anywhere on this site. Published values for microchannel closure vary widely with needle diameter, depth, skin site and measurement method, which is exactly why quoting one as though it applied here would be misleading. What can be said without a measurement is the shape of the thing: the window is short, it is why the ampoule is dispensed on contact rather than applied afterwards, and it is why the cadence is once a week rather than daily.

Most absorption routines are two actions. You needle. Then you apply. The gap between them is different every single time, and the channel starts closing the moment it opens.

The Tap Pen releases its paired ampoule at the moment the needle meets skin. The device and the ampoule are physically coupled. Timing stops being something you have to get right.

There are three things to set before a session, and they are set in three different places. Depth is the collar on the body, and turning it moves the needle out or back in. Flow is a ring on the cartridge, and it sets how much ampoule the tip releases. Intensity is the button on the body, six levels, with the level shown on the on-body display so it is never something you have to remember.

None of the three reads another. Turning intensity up does not move the collar, and it does not change what the cartridge releases. Moving the collar does not change the level on the display. Each control does one thing, and it keeps doing that one thing whatever the other two are set to.

Fusing controls is the cheaper arrangement and the easier one to sell, because one dial that moves everything needs only one label. The cost is that every change becomes a trade. You ask for more of one thing and you accept more of another, whether or not the second one was what you wanted.

There is also an arrangement in which flow does not exist as a control at all. If the device does not carry the formula, the amount on the skin is whatever was applied beforehand, so there is nothing on the device to set. Putting the ampoule inside the cartridge is what turns that into a position on a ring.

The depth collar is continuous. It does not click, it does not stop at the marked values, and it stays where it is left. The numbers printed around it are labels on a range, not the only places the ring can sit.

A stepped dial makes a smaller promise. It offers a list, and any depth you want has to be rounded to the nearest item on it. Skin does not arrive in five sizes. It is thinner at the eye than on a cheek, it differs between two people of the same age, and it differs on one person between a first session and a tenth.

Continuous means the setting is the position you picked rather than the closest one a menu allowed, and it means the position is yours to keep. If 0.8 mm is where you work, the collar sits at 0.8 mm, because nothing pulls it to 0.75 or to 1.0.

The two controls you turn by hand behave in opposite ways, and that is deliberate. Flow clicks, because three positions can be counted by feel and you should be able to find the middle one without looking. Depth does not click, because a range cannot be counted. What you give up is the click. What you get back is every value between the marks.

The cartridge comes off the device, the ampoule goes into it, and it seats back on with a push. The formula is inside the tip before the first tap, and it is released at the moment the tip meets skin.

The ordinary arrangement is two actions in an order. You needle, then you apply, and the interval between them is a different length every time. Loading the tip removes the second action, and the interval with it.

It is also what makes flow a setting at all. Because the tip holds the formula, the amount that comes out is a position on a ring rather than a consequence of how much you poured into your hand.

None of that is a statement about how much of an ampoule crosses the barrier. Loading the tip changes when the formula arrives and how it is metered. What happens after it arrives has not been measured by re:tones, and the claims ledger at the foot of this page leaves that row open.

Both ship in the box. They are not interchangeable.

PRO-R Nano is a round plate on a heavier needle. It is the forgiving one, and the one to start on while you learn pressure and pace.

PRO-5D Nano is the square plate, set at 45 degrees, with the 8 µm lattice. It is the everyday one.

Geometry is not decoration. A round plate meets skin evenly from any angle. That matters while your technique is still uneven.

A square plate tiles cleanly across a flat area. That matters when you work across a cheek.

Both are sterile. Both are single use. A fresh one each session.

An ampoule built for an open channel is a different brief from one built to sit on a surface. Two things change.

First, the format has to stay closed. You are applying to a barrier you just opened on purpose. A pump does not. It draws air, and it holds residue in the nozzle. So the format is crimp-sealed medical glass, opened once, by you.

Second, the concentration has to be worth the trip. All three ampoules are 50 mL in the same vial. The figures below come from the manufacturer's own ingredient statement.

There is a shorter, warmer version of this page that we chose not to write. It would say the device works on lines, that it wakes something up underneath, that skin rebuilds itself afterwards. Those are the easiest sentences in this category to write, and every one of them is absent here on purpose.

A claim does not only describe a product. It can change what the product legally is. Say that a device acts on the living biology under the surface and you have not written a bolder sentence about the same object, you have moved it into a different category with a different set of rules attached to it. The wording is enough to do that on its own. The hardware never has to change.

So the copy stays on the side we can account for, which is what the device does mechanically. A needle diameter stated in micrometers. Temporary channels through the outer layer. A collar you set by hand between 0.5 and 1.5 mm. An ampoule released at the moment of contact. Each of those is a fact about an object, traceable to a specification or to the thing in your hand.

What follows inside skin is not ours to narrate. We have not measured it, and we are not going to fill the gap with language while we wait. That is why there is no efficacy percentage on this site, no before and after, and no account of what your skin is doing in the weeks after a session. The grades and the ledger below list what is missing rather than hiding it.

What is printed instead is the rest of this document. Every figure on this site carries the thing it rests on and the grade that goes with it. 8 µm and 15 µm for the two cartridge geometries. 0.5 to 1.5 mm of collar travel, set by hand. 210,000 ppm of niacinamide printed next to the 21% it converts to, because those are two rulers for one quantity. None of it is decoration. Each figure is a claim, and each one is in the ledger below with its basis beside it.

It is much easier to write a phrase that sounds like a specification than to print one. Surgical grade stainless steel is the type of phrase we mean. It reads like an engineering term and it is not one. It names no alloy, no composition, no supplier and no lot, so nobody can check it and nobody can compare two products by it. From the phrase alone there is no way to know whether two things carrying it are made of the same metal. It is not on this site, and neither are its relatives. Where the alternative is language of that kind, we print the figure or we print nothing.

The rule costs us as much as it earns. The needle surface is now named, because the manufacturer has stated it in writing, and it carries the lower grade that a written statement earns. The rest of the cartridge is still not named by grade, and it will not be until the manufacturer states it in a form we can print and stand behind. Needle count per array, battery capacity, charge time and weight are absent for the same reason, listed as outstanding in the specification above and graded in the ledger below rather than estimated into existence. Nine measurements are specified in our brief to the manufacturer and not one of them has come back. Further down this page, What we have not measured yet prints the exact sentence each of those reports would let us write, with the blanks still showing.

Stated plainly, that is the standard this document is written to, and it is a standard we set for ourselves rather than a comment on anyone else. A figure appears here only with its source attached, and a sentence that needs a figure we do not have does not appear at all. It is a slower way to write a page, and it is the only version of this one we can defend line by line.