SeaKing Stores › 10ft 13-pin extension cable - PMX-8 system - PMX10C 10ft 13-pin extension cable - PMX-8 system - PMX10C £35.00 10ft 13-pin extension cable - PMX-8 system - PMX10C. 13-Pin 10 ft Extension Cable for PMX-8 System. PMX-8BB to PMX-8DH. Useful ancillary stock for complete marine installations. Add To Cart Added! 10ft 13-pin extension cable - PMX-8 system - PMX10C. 13-Pin 10 ft Extension Cable for PMX-8 System. PMX-8BB to PMX-8DH. Useful ancillary stock for complete marine installations.