Load it once. Dial it after that.

You fill a sterile 3mL glass cartridge one time and drop it in. Every session after that is three moves: dial, dispense, done. No drawing up a fresh syringe, no holding a barrel up to the light hunting for a graduation mark.

The filling step happens once per cartridge instead of once per session. That's the whole reason the pen exists.

0.01 mL per click. You feel it, you don't read it.

The dial has 60 click stops, and each one is a mechanical detent. A fixed step in the hardware, not a mark you interpret. That's why the same dial position gives you the same amount on your fiftieth session as on your first.

Repeatability comes from the mechanism, not from your eyesight or the lighting. The dial stops at 60, so 0.6 mL is the most in one turn.

Machined aluminum. Built to outlast the cartridges.

Solid body, firm mechanical click, protective cap, a reusable instrument, not a disposable. It's 6.3 inches and 1.76 oz, slim enough to live in the fridge door with a cartridge already loaded.

Reviews

FAQs

Please read our FAQs page to find out more.

Does the pen comes with a cartridge?

No, the pen and the cartridges are separate purchases, and you'll need at least one cartridge before the pen does anything. We sell them in 10 and 20 packs, steam sterilized and individually sealed.

If this is your first pen, take the 10. After a month you'll have a much better idea what you actually go through, and the 20-pack will still be here.

V2 or V3 — which one do I buy?

Whichever one you like the look of. They're mechanically identical: same 60-click dial, same 0.01 mL per click, same cartridge.

The V2 is the cheaper of the two. There is no "more accurate" model, so you're not trading away precision either way.

Do I have to refill it before every session?

No, and that's the whole point of the pen. You fill a cartridge once, drop it in, and every session after that is dial, dispense, done. The filling step happens once per cartridge instead of once per session.

New pen feels stiff. Is it faulty?

Almost certainly not. That's the mechanism bedding in, not a fault, and a brand-new pen tested this way looks broken when it isn't. Resistance is the sum of several things and they stack — a fine tip on a cold, slightly viscous solution feels far worse than either problem alone.

Do you sell pen tips?

No, we do have recommendations over at the Pen Tips page.

The pens take standard universal screw-on pen needles, available anywhere they're sold. Fresh tip every session.

Does it come pre-filled?

No. Pens and cartridges ship empty. It dispenses whatever you put into the cartridge, at the amount you dial, and it has no opinion about what that is.

How fast does it ship?

Orders process in 1 to 2 business days from U.S. fulfillment centers, tracking emailed automatically, plain box.

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