This is a tool that is useful for replacing nipples and/or spokes. It’s especially useful for Double wall rims and deep well aero rims. The tool has a small spring clip that inserts into the nipple and allows the user to thread the nipple through the spoke hole onto the threaded end of the spoke. Clever idea. The average enthusiast probably wouldn’t use this however the bike mechanic who works doing tune ups and repairs would enjoy the efficacy of this tool. I’d recommend it.