10-040450-018 is a plain flat sealing gasket designed for use with MIL-DTL-5015 and MIL-5015 type standard cylindrical connectors. This synthetic rubber gasket provides waterproof and pressure sealing features for flange mounted receptacles. For shell size 18, the gasket features dimension A of 1.063 ±0.10 inches, dimension B of 1.125 ±0.16 inches, dimension C of 1.375 ±0.00 inches, and dimension D of 0.203 ±0.10 inches with a thickness of 0.031 ±0.010 inches. The gasket is commonly used in military and industrial applications where reliable environmental sealing is required for cylindrical connector assemblies.