This cylinder is used to replace the cylinder in a Dlx90. Elbows are included and installed. To install, remove the rear target door and 1/4" bolt. Disconnect all the air supply hoses from the cylinder and the E clip that retains the cylinder head on the target holder. Remove the 1/4" nut that holds the cylinder on the standoff and slide the cylinder free. Then, reverse steps to install the new cylinder.