I use a 5" length of 3/4" copper tubing with a 3/4" copper end cap. Initially, the cap will fit with some slight friction. As it is used, it loosens a bit, but no problem. I simply attach the end cap, insert the hair (usually bucktail), tap a few times on the cap, slide the cap about halfway off, tap on the side to bring the hair back down to the end cap, remove the cap, and voila! Works great and the 3/4" dia. allows easy entry of the hair into the tube. Good luck.
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