Natural chockstones – which are stones or boulders already wedged in cracks – have been used in belaying/anchoring for the protection of climbers since the sport began. Subsequently, climbers carried their own pebbles or ‘chocs’ which could be inserted into a vacant crack with a rope sling threaded around it. The next stage (circa 1950) was to file out engineer’s nuts (as in nuts and bolts) to remove any rough edges and thread them on a rope sling for use as required. The big advantage was that several different sizes could be carried on one sling. We’ve got an excellent example of the system here in the collection: two nuts threaded on an early type sling which we suspect dates from around 1965. The donator, John Hinde, was a long time stalwart of the RAF Mountain Rescue Service, and gentleman of the hills.