The Edelrid Pure Slider won the Best in Show award from Rock and Ice Magazine at Outdoor Retailer when they were released, and for good reason. The sliding locker system is ideal for use with one hand, something traditional locking carabiners have a hard time doing. And because it doesn't carry any extra bells and whistles, this carabiner comes in at an astonishingly light 42 grams (1.5 oz).
It's slide lock system allows for easy opening with one hand, even while clipping the rope. This allows you to use it as a quickdraw for long runouts when you need to trust that your last clip won't fail you. Or it can be used as a convenient and safe top-rope anchor when you won't be able to see if the carabiner has become twisted - potentially leading to a gate being open and failure of the system.