RAM-B-316-TRA1-NRU is the transducer kit used with the RAM TRA1 series of transducer mounts. It includes the RAP-202-TRA1U transducer base with .5 inch female flex rod. It also includes the RAP-321U RAM male octagon button with .5 inch pipe clevis and RAP-B-200-1U single socket arm for 1 Inch ball with octagon female opening. The RAP-321U and RAP-B-200-1U are normally used to attach to a .5 inch diameter RAM aluminum rod on one end and RAM 1 inch diameter ball accessory on the other end. The RAM transducer arm mount is compatible with most transducers which attach using a 1/4" bolt/screw.