Twist-lock karabiner that incorporates an integral braking system for improving friction on descenders and belay devices. Works extremely well with the Grigri when using slimmer ropes such as the Beal Booster, which can normally be a struggle.
Many pulleys require an oval-shaped carabiner to work properly. The OK carabiner from Petzl was designed for just that. It's also very useful as a general purpose carabiner at belays and for caving cows-tails.
The Petzl Omni fills a niche market for semi-circular, alloy karabiners. Primarily used for securing harnesses that use two attachment point that must be connected (such as the Petzl Super Avanti) or where there is likely to be a 3-way load.
The most important feature of this patented carabiner is that it allows the user to vary the descent simply by moving the rope into the narrow section of the carabiner, eliminating almost all downwards force. In addition the carabiner is equipped with a stainless steel twisted ring which can be clipped into the semi-circular maillon on the harness. This ring makes this carabiner suitable for all descent speeds on any type of rope.