The lockwashers, panel nuts and rugged gaskets are designed to aid in mounting the HD30 and HDP20 Series connectors. The lockwashers are used to add tension between the threads and the nut to provide a secure mount. The lockwasher and the panel nut should be used together. The rugged high quality neoprene gaskets form a tight seal between the panel face and connector flange to help keep out destructive elements. Rated to operate in environments from -70F to +225F. Panel nut 24 shell plastic.