Amulet of guarding
The following information pertains to an upcoming version (NetHack 3.7.0). If this version is now released, please verify that it is still accurate, then update the page to incorporate this information.
Wearing an amulet of guarding provides 2 AC and augments magic cancellation by 2, similar to a ring of protection. Eating an amulet of guarding has a chance to increase intrinsic protection by 2, but does not affect magic cancellation.