The current industry standard for testing the water-tight integrity, accuracy, and overall function of depth gauges, watches, dive computers, and certain underwater photographic gear. Each chamber is constructed with a rugged steel structure. The cogged lid with clear acrylic lens is designed for strength and ease of operation. Standard “Depth” chambers have gauges with 1% accuracy. While, “Instrument” chambers have high accuracy, 0.25% accuracy gauges. It is specifically designed to test today's highly sophisticated dive instruments. It features a 4.5" Test Gauge with 1/4 of percent accuracy to 300 feet of salt water (that's 0.75 ft!) The gauge is calibrated in both feet (300) and meters (90) of depth and has an anti-parallax mirror for obtaining highly accurate readings. Each unit is equipped with Bulkhead Air Shunt and Swivel as already described.