London Underground Certificate No. 296 COMPLIANT TO LUL STANDARD 1-085-A3 Rail Approval REACh RoHS BS EN IEC 61386 CE. SSU M Fixed Externally Threaded Conduit Fitting. SSU M fixed externally threaded conduit fitting. Two part, comprising shell and body with external thread. This fitting can be inserted into a knockout and secured with a locknut. Stainless steel 316