Thread x Slip Bulkhead Fitting Thread X Slip Bulkhead Fittings are bulkheads that have interior thread on the large flange side of the bulkhead and a smooth interior on the smaller section. The most common use for this bulkhead style is in the side wall of an overflow box or back wall of an aquarium. When used in the side wall of an overflow box a 3/4 in bulkhead allows for LocLine to be threaded into the thread side and a slip x hose barb elbow used in the smooth slip side. When used in the back wall of an aquarium the thread side will allow threaded screens to be used on the inside of the aquarium and slip PVC pipe to be glued into the smooth slip side. Please remember the rubber gasket always goes on the water side of the fitting.
