81665-4 is a neoprene flange seal designed for AMP circular connectors in shell size 13. This seal is manufactured from neoprene material in black color and is used with one-piece or two-piece sealed circular plastic connectors in the CPC series. The flange seal provides peripheral sealing for receptacles, ensuring environmental protection and connector integrity. It is compatible with sealed CPC receptacles and is part of the comprehensive sealing accessories lineup for commercial signal and power applications. The seal dimensions are 1.500 inches (38.1 mm) outer diameter and 1.125 inches (28.58 mm) inner diameter, making it suitable for panel-mounted or free-hanging receptacle configurations.