The Alde marine gas leak detector (bubble tester) is designed to be connected close to the outlet side of the gas regulator. It then provides an instant visible check for leaks. Bubbles in the sightings chamber indicate a leak downstream of the bubble tester. Supplied complete with fluid. It may be used in boats, caravans and other applications. This bubble tester is approved under the Boat Safety Scheme. Suitable for LPG.