Hidden spoke nipples cheat wind, but require specific equipment like Park Tool's innovative SW 15 3 Way Internal Spoke Nipple Wrench. The SW 15 features a 3. 2mm square drive, and both 5 and 5. 5mm hex drive sockets. The low profile walls fit perfectly in the tight surroundings of most rims, and the Park Tool blue vinyl coating offers a secure grip. This wrench works with wheels made by FSA, Blackwell, Planet X, HED, Rolf, Bontrager, Campagnolo, and Mavic. Like all Park Tools, the SW 15 3 way Internal Spoke Nipple Wrench has a lifetime warranty.