A clipper leash for Black Diamond Viper and Cobra axes.
It is supplied with an attachment that bolts into a hole in the shaft, and there are two types of this depending on whether your axe is the original silver model or the more recent bronze or current black one. The latter also fits the carbon fibre Cobra.
As a clipper leash it suffers slightly from the fact that wet snow can pack in behind the bit you squeeze to unclip it meaning that you suddenly can't unclip them any more - however there isn't much in the way of an alternative!
NB The price is per single leash.