Assuming you still have the Congo, JM, and Flintstones. They should all have 28 1/2 inch legs, Williams style with the full length rib. The Creature should have the same legs, just finished in charcoal grey. The Top (head) height of the machines can certainly vary depending on what pitch you prefer to have them, but the front should be real close if the front casters are all the way in. Pretty easy, just measure them all and you'll know what you have. If all else fails order a pair of these to play in!