Circular Waterproof Connectors Amphenol LTW Circular Waterproof Connectors are available as a receptacle, receptacle connector with cable, and over-molded with cable. The field-installable options are available in multiple sizes mini, standard, middle, and large. Amphenol LTW Circular Waterproof Connectors offer ≤10mΩ contact resistance, ≤100MΩ at DC500V insulation resistance, and at least 1000 mating cycles.