THIS IS THE UNDERFRAME FROM TANK CAR KITS 4020 & 4025. IT IS FOR 8 - 10,000 GALLON CARS BUILT FROM THE 20'S TO THE 50'S. IT INCLUDES THE K-BRAKE CYLINDER, SADDLES, AND WARNING PLACARDS. IT IS A STEEL CENTERSILL WITH WOODEN SIDE WALKS. THIS KIT IS INJECTION MOLDED IN GRAY STYRENE.