This NetHack ring bestows the stealth intrinsic. This has little game effect other than quieting your footsteps so that you don't wake sleeping monsters in a room when you walk in.

This ring can occasionally be useful in conjunction with a ring of invisibility or speed boots. It's not a bad idea to polymorph into a metallivore and eat the ring (if feasible); the risk of losing the ring is probably worth taking in this case. In general, wearing the ring of stealth isn't worth the added hunger effect.