A8504939S11W is a QPL connector backshell accessory manufactured by Amphenol PCD for military and aerospace applications. This backshell provides strain relief, environmental protection, and EMI/RFI shielding at the termination area of circular connectors. The product is designed to meet SAE-AS85049 standard requirements and is suitable for use in harsh and demanding environments. Common applications include military, aerospace, and industrial systems where reliable connector protection and cable management are essential.