Wild Country Rock 14 The original Rock design was developed 19 years ago by Mark Vallance and has been refined over the intervening years to create the definitive piece of passive crack protection. The unique shape is engineered to take up the most stable position in any crack, the convex side locking against the two feet' of the concave side, creating a stable triangulation of forces see inset. Planar side tapers ensure stable side placements and allow you to turn key' rocks into pockets. The over barrelled edges and corners together with the use of carefully selected 6064 T6 aluminium extrusions ensure rocks bed' into the crack but can be cleaned' easily. Note that this item of climbing safety equipment is non returnable. Please call us toll free at 877 236 8428 or e mail bentgatebentgate.com with any questions.