Available in 3 sizes. Small for 8mm-12mm joints. Medium for 15 - 38mm joints and large for 45mm and upwards. The medium and large cotter pins require the small M3 washer. The small pins are just used withh the extra small washer in the 12mm size.

Small Cotter Pins - approximately 2.5cm in length, suitable for 7mm - 12mm joints.
Medium Cotter Pins - approximately 3.5cm in length, suitable for 15-38mm joints. 
Large Cotter Pins - approximately 5cm in length, suitable for 45-57mm joints.