Steel coupler is splined on one end and has a 3/4" round hole on the other.
Fits big GM gear box for pre 1978 vehicles.
When ordering, select applicable hole size/spline needed.
Warning: This coupler is splined 13/16 x 36 all the way through. It fits OK on 3/4" round shaft for welding, even though it has interior splines.
Coupler = 2" L x 1.060" D