The Keene Super Crevice Sucker is an excellent tool for cleaning out water filled pockets and crevices both above and below water. It even can be used to vacuum loose dry material out of hard to clean locations. The A23 models has a 3″ diameter vacuum chamber with a long draw plunger that produces good suction with plenty of volume. A hole on the upper end reduces backpressure and doubles as an easy dump port for your collected material. The 12″ removeable crevice tip features an inset tube much like that seen on snuffer bottles that keeps collected gold from escaping. The vacuum tube can also be used without the crevice tip to draw up larger gravel from underwater and hold it by rapidly inverting the tube, then dumping in a bucket or sluice box.