The sole best piece of armor you can get your hand on, dragon cuirasses are [[Invincible Items|indestructible]] and have a very high AV due to being generated mainly with [[dragon hide ]] as its [[Materials|material]], but can also be generated with [[mithril]], [[octiron]] and [[damascus steel]].
Due to an oversight confirmed by Lampshade, a dragon cuirass can be hardened or changed into a different material.