This is a 7/8 inch Trailer Castle Nut used to secure your Heavy Duty Equalizer Bar to your Trailer Spring Hangers. This is the Cotter pin that is typically included in Heavier Capacity Tandem and Triple Axle Spring Hanger Kits, like the one seen here. The Bolt Diameter for most Equalizer bars for 2" wide Leaf Springs is usually 7/8". As long as your 7/8" bolt has a hole for a cotter pin, and is 7/8" - 9 UNC thread, this castle nut would work for you.Specifications- 7/8 - 9 Coarse Thread Trailer Castle Nut- Steel Construction- Fits 7/8" diameter trailer spindles