Doesn't look like much but this "kit" or bundle of spare parts can help in a pinch. BD 01's are susceptible to having the plastic heel lever snap off when you put them on and of. I've snapped 2, and my spring pre-load was < than 1 cm. The spare heel assembly saved me. I never had to use anything else from the kit. It is possible to just buy the heel assembly direct from BD, but the spare heel wires and stuff are nice to have around in case you lose one. BD 01's are good bindings, but you'd be wise to have some spare parts on hand...