Curt Manufacturing 48830 Towing Wiring Replaces the trailer ball in any CURT ball & pintle combination Fits 2 5/16" couplers or a lunette eye with a 2 1/2" or 3" inside diameter 1 1/4" diameter shank for maximum strength Fine threads and self-securing nylock nut for secure mounting Constructed from high-strength, drop-forged steel