Ring of regeneration
While wearing a ring of regeneration, a character's HP is healed by one every move that the turn counter is increased (even if wearing more than one ring). This allows a player to easily identify a ring as regeneration by putting on the (ideally noncursed) ring, kicking a wall, and examining his healing rate. The normal (i.e. regenerationless) healing rate is some HP every few turns.
Unfortunately wearing a ring of regeneration burns nutrition very quickly: every odd-numbered turn your nutrition is decremented. Thus, a player should only wear one if he's hurt, or about to become so, or if he is satiated and wishes to become less satiated quickly so as to be able to eat corpses for intrinsics.
Dropping a ring of regeneration into a sink produces the message, "The sink looks as good as new."
