I have a hawk and several other machines that I run the T-tech system on...If your running a t-tech system on any machine other than the cheyenne hawk, the rubber grommet/sleeve is not that big a deal. you can remove and clean and sterilize your T-tech tubes like any other tube...It is however a great big deal if you use a hawk machine..the leakage that occurs in the T-tech cartridge, and yes, I've had that happen to me, will destroy..let me repeat, DESTROY the hawk handgrip depth adjustment.. I've gone through 2 hawk grips in less than 3 months and i have a friend who uses T-tech's on his spirit and he's gone through 2 grips in less than 3 months..Its not so much the ink that is a problem, most ink is too thick to leak back into the grip..the devil is washing out your tips between colors. its water leaking back into the grip that corrodes and ultimately ruins a hawk grip