Center bar kit to hold 2 units together (no rack ears included), *READ CAREFULLY* kit has 2 screw-in internal (must fit into 1+1/8") side panels with screws which then use center locking clamp assembly (with twist lock) and 1"x1.75" truss with screws. Note: older DBX unit will not fit this kit, only 163/162 designs with newer version chassis.