The MLS (Modular Locking System) line of steel plate targets will work with all of our MLS Hangers, including the MLS T post bracket, MLS 2x4 Cap, MLS 2 Target package, and our Plate Rack in a Bucket. The "Locking" portion of the name refers to the way the targets are hung on the hangers. To set up the target, it will need to be put on the hanger 90* from vertical, and then rotated down. This ensures the target will never "jump off" of the hook no matter what you're shooting it with. Another great feature of the MLS steel plate target line is that because there is no welding on the HEXALLOY 550 HEXPLATE (by the way, welding on target steel is very bad for it and weakens it tremendously), the target is very easily reversible which allows you to shoot one side with pistol and one side with rifle so you never have to worry about fragments coming back towards the shooter at closer ranges. All of the MLS (Modular Locking System) steel plate targets and hangers are made from 3/8" thick HEXALLOY 550 HEXPLATE, and are great options for everything from rimfire rifles and pistols to centerfire rifles and pistols.