Alde LPG Leak Detector 8mm The 4071 Leak Detector is intended for in-line installation, and should be connected into the gas system close to the outlet side of the regulator. It provides an instant visible check on gas soundness from the outlet side to each installed appliance, a leaking system being positively indicated by bubbles appearing in the glass-sighting chamber. The Boat Safety Scheme and the new British Standard both recommend that one be fitted in an installation. Part Number 4071-085 Genuine Alde Part