Impervious Rapier of Defending +1
An impervious weapon is warded from damage and decay. A metallic weapon cannot rust and a wooden weapon cannot rot or warp, even by magical or supernatural means. An impervious weapon gains double the normal bonus to its hardness and hit points for each point of its enhancement bonus. The break DC for an impervious weapon and the wielder’s combat maneuver defense against sunder maneuvers against the impervious weapon each gain a bonus equal to twice the weapon’s enhancement bonus.
A defending weapon allows the wielder to transfer some or all of the weapon’s enhancement bonus to his AC as a bonus that stacks with all others. As a free action, the wielder chooses how to allocate the weapon’s enhancement bonus at the start of his turn before using the weapon, and the bonus to AC lasts until his next turn. This ability can only be placed on melee weapons.