The HydroDome is designed to attach to a standard pool pole to isolate a light, the main drain, side suction, return, etc. When held against a leaking light, or other isolated areas, the user will hear the sound of water entering through the microphone chamber identifying that there is a leak at the isolated area. It’s that easy. The same test can be performed on main drains. In the case of dual main drains, the weighted dome will seal off the extra drain to determine whether the drains or trunklines are leaking. The HydroDome is ergonomically designed for a single user to listen without bending or kneeling while pumping or mechanically affixing the unit to the light. The neoprene gas injected gasket will allow for rough or uneven surfaces.