For now, I'm just using the stock mouthpiece, there's a small cartridge inside that can be pulled out and the mouthpiece is just a hollow cylinder. It's plastic, so the hole on the tip can be widened for easy dripping, but I'm just taking the cap off everytime I drip. I've been fooling with ideas of adding a 510 collar to the atty so the T-tip can be added. Since the mouth piece slips over the main body of the atty, it lacks a collar that the T-tips are all meant to slip into, David would have to machine one that slips around the outside of the atty. The only drawback of a "401 T-tip" is that it cancels out the main advantage the 401 has for dripping, a completely exposed bridge that allows you to set the dropper directly on it rather than dripping liquid down a collar, this makes flooding less probable since you have more control and can see when the wick is saturated.