This sea-green crystal always feels moist to the touch.

A crystal of aquatic action aids the wearer while underwater.
Any armor bearing this augment crystal does not impose an armor check penalty on your Swim checks, you also gain a Swim speed equal to one-half your land speed (round down to the next 5-foot increment), and you also take no penalties on attacks or movement while underwater (as if under the effect of freedom of movement) and you can breathe water as easily as air.

Prerequisites: Craft Magic Arms and Armor, freedom of movement, water breathing.
Cost to Create: 1,500 gp, 120 XP, 3 days.