This kit is intended to be used with any Revell Space Shuttle Orbiter kit and provides replacement main engines, OAMS pods, and more. The resin parts are molded with crisp details and no visible airholes. The main engines are nicely detailed with cooling tubes molded in place. There is a bit of flash on some of the parts and all parts except the rear engine mount/body flap are still attached to their pour plugs. Photoetched parts provide payload bay hinges for the various orbiters, the side hatch and rear umbilical plugs. The instruction sheet consists of several drawings showing where to use the parts on the Revell kit.