81665-5 is a neoprene flange seal designed for use with shell size 23 sealed CPC (Circular Plastic Connector) connectors. This sealing accessory is made of black neoprene material and is used with square flange receptacles in one-piece or two-piece sealed circular plastic connector configurations. The flange seal provides environmental protection for panel-mounted connector applications. It is compatible with TE Connectivity's AMP circular connectors for commercial signal and power applications, ensuring reliable sealing performance in various industrial environments.