The Petzl Ok Oval Screwgate is a lightweight oval aluminium carabiner that allows optimal loading of devices with a wide cross-section, such as pulleys.
Oval carabiners are the best choice of carabiner where any pulley is to be used as the pulley will sit centrally and be more likely to stay in a correctly loaded equalised position. The symmetrical shape means that a pulley can be used on either side, keeping things simple.
Other points to mention are the Keylock nose, to prevent snagging on ropes, gear etc., and a red visual indicator shows when the carabiner is unlocked for enhanced safety.
If you are looking for a crab and pulley for light load situations, consider the Petzl Ultralegere Pulley Wheel as an additional product that works perfectly on this OK Oval carabiner.