Locking nut is reversed threaded, the bulkhead fitting with 4mm thick silicone seal gasket that will to the shape of the round barrels Threaded connection and embedded gasket form a tight seal, not easy to slide and leak Suitable for commercial plumbing, aquariums, water tanks, irrigation, swimming pools and water parks Easy installation: Can be installed on the wall, water tanks or panel Made from PVC, will not fade, cracks or peeling, and can be used long terms