The TRIPLEX is specifically designed for rock climbing and is comprised of 3 parts for the ultimate in simplicity, ease of removal, inspection and convenience of reuse. The one-piece bolt and expander wedge is activated by the external 17mm nut which eliminates potential hidden thread and expander cone corrosion deep in the hole. TRIPLEX BOLTS can be used in all types of rock - including soft and pocketed limestone. All stainless steel for the absolute corrosion resistance. Use special 12 mm drill bit - fits popular holders and all power tools with SDS.