McMaster 98338A558 Zinc-Plated Carbon Steel Cotter Pin, 1/4" Dia × 4" Long, Pack of 50

Lock the ends of clevis pins and shafts to keep components in place. Slide these cotter pins into a hole and then bend the prongs outward with pliers to secure. Also known as split pins, one prong is slightly longer than the other for easy opening once inserted. Repeated bending will weaken the pin, so they should not be reused.

Zinc-Plated Carbon Steel — These pins withstand occasional exposure to moisture. However, since friction from moving parts can wear away the finish, they're not ideal for wet environments. While not nearly as corrosion resistant as stainless steel, they are stronger and won’t deform under stress.