I bought these for my big rig - then sold my big rig. These are in almost mint condition. The wheels show some use, but that's about all. These adjust to fit tripods with tip-to-tip distance from 45" to 53", and the tip recepticles are 3" i.d. These have the 5" wheels, which are a $95 option. These are VERY heavy duty, but they roll around very easily. New, these sell for $259 + $75 for the wheels + shipping. I'm asking $250 shipped CONUS. If you don't like that price, make me an offer. (Schroedinger the Cat is not included.) Thanks!