Finding the right size is simple. Whether you need the clevis pins, locking pin, trailer coupler pin, cotter pins heavy duty, lynch pins, we have the size you need for a perfect;. COTTER PIN (M1.6 25-30pcs, M2.5 25-25pcs, M2.5 30-25pcs, M3.2 30-20pcs, M3.2 40-16pcs, M4 60-8pcs).