Hayward Flow Control CCP Series Tank-Tite compression fittings provide a constant load on the gasket of a bulkhead fitting to overcome and compensate for tank wall expansion or contraction due to changes in temperature and/or pressure within the tank; they also maintain a constant load on the bulkhead fitting nut to reduce the possibility of loosening due to vibration within the system. The fittings have a PVC upper- and lower-body construction, 17-7PH stainless steel wave spring and a rating to 150psi non-shock at 70