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Kong Climb Speleagle Hammer 432373. It can be used to tighten 13 and 17mm nuts. Fitted with an ergonomic rubber handle and safety sling.
Compared to other hammers, Kong's Speleagle is more compact and particularly suited for minimalist mountaineering missions and caving scenarios. The stainless steel head is incredibly light and solid at the swing, and the bottom has a wrench that can assist with spinning bolts. The rubber handle has 10mm tape for assured longevity.