In summary, the Amphenol AT Circular Series is ideal for heavy duty applications and is available in nine, five, and three pin layouts with a quick mating reverse bayonet coupling system. The connector is made from durable thermoplastic material and comes in a jam nut version, which is great for quick installations as it requires no screws, or a square flange version. ATC meets the SAE J1939 specification, is environmentally sealed against moisture and contaminants all while being RoHS compliant. This is a low cost high value interconnect system featuring field installable contacts, for anyone who wants to play nice with harsh environments.