The SUU-20 used either the long or the short breeches, they were not interchangable. I believe that both breeches used the 863 carts. I still have an expended 863 cart on the shelf here. A Weapond supervisor at MacDill told me to go in on weekend standby and arm three F-16s for bombing competetion out west somewhere. He told me the breeches were on the bench in the D flt office. I asked whether they were the long or short breeches. He rudely said, "Damnit, just do as I said put those breeches in. I did as he said and by the following week, word came down that of the three planes, not one bomb would come off. When I told them of my conversation with the supervisor, they didnt need to talk to me again to resolve what happened. The short breeches would not work for SUU-20s designed for the long breeches and visa-versa. I do remember seeing stenciling on SUU-20s stating "LONG BREECHES ONLY" or "SHORT BREECHES ONLY" in red. Not sure if that is still the case.