M163 Vulcan Air Defense System (VADS) is an M113 vehicle with a 20mm M167 Vulcan mounted on top of it, used for short-range air defense. It has a short range radar used for tracking targets and establishing a firing lead for the gun. It was in service with the US Army from 1968 to 1994, but still remains in service with certain armies. Its M113 platform makes it able to traverse shallow rivers, but doesn't make it amphibious.