Mithril-coat

The dwarvish mithril-coat and elven mithril-coat are two types of body armor found in NetHack. While neither is as effective as a good suit of dragon scale mail, they are both much lighter than other high-AC suits. They are also the only suits of body armor that provide MC3.

Being made of mithril, they are immune to erosion, though they will still hinder spellcasting.