Front Zip Locker by Yukon Gear and Axle. The Yukon Zip Locker is the latest in on-demand traction. Its air-operated design allows you to switch from an open differential to 100% lockup when you need it, giving you the ultimate in driver selectability. On the street, at the track or off-road, you can trust the quality and strength of Yukon Gear and Axle. Let the Locker transfer power for whatever your needs may be! If you�re looking for the latest in on-demand traction, then the Zip Locker is for you.