Easy to install, easy access for maintenance.Vermin proof with large screened air vents . Greater clearance for submersible pump cable . Stainless steel hardware . O-ring system ensures reliable watertight seal between well casing and retainer ring . A second O-ring is used to seal cover and retainer ring, a positive compression seal is achieved by tightening 4 bolts .https://www.aquascience.net/boshart-industries-thread-compound-for-stainless-steel-fittings-1-2-pint-8-fl-oz