A high quality forged steel U-Joint designed to attach ROTO-BORE drill rods to plow and trencher boring motors that are equipped with a 1 3/8" - 6 spline PTO Shaft. To accommodate the hex shanks of our drill rods this unit must be used in conjunction with our ADC-1300 adapter for 13/16" rods, ADC-2300 for 1" or ADC-1000 for 7/8"