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.