The Smc Nfpa Locking D Series Carabiner Is A True Representation Of Timeless Quality And Attention To Detail. As One Of The Most Versatile Mid-sized Locking Carabiners On The Market You Will Find That Form And Function Are Unsurpassed. The Enduring Design Of The Smc Locking D Has Become A Standard In Rock Climbing, Mountaineering And Rescue Applications As Well As In Ever Increasing Industrial Applications Due To Its High Strength, Light Weight, Wide Gate Opening And Overall Functional Versatility.