This fits your .
577-5116 Features: -Concentric openings. -Measures 2'' from center of adapter opening to center of square drive for easy torque calculations. -High strength, thin wall design. -Applies up to 15% more torque to fastener. Dimensions: Overall Product Weight: -0.1 Pounds.
Proto torque adapters are designed with a center-to-center dimension of 2". This means that the distance from the center of the square drive of the mating torque wrench to the center of the fasteners is exactly 2". This constant dimension serves to simplify the process of calculating the torque applied. The box end wall thickness is specially engineered to provide strength while still allowing ample room for access to reach difficult fasteners.
Stanley-Proto J5116 3/8-Inch Drive Torque Adapter 1/2-Inch - B001HW8Z0C