Aqua Lung Pearl Scuba Diving Womens BC (Twilight, Medium-Large) Hybrid air cell combining the best features of a jacket style and a back inflation unit Sleeker, low profile lobes with scalloped lower edges to rise above the hips The patented, integrated sports bra provides added comfort, security and stability The flat E-Valves reduce drag and keep the BC streamlined. The valves are one-way to keep water out The SureLock II weight pockets align themselves. Just insert the pocket until it "clicks". A simple, single pull release is all that is needed to jettison the weights in an emergency