The DY-8F dolly is designed for the 507QF and 508QF tripod systems, providing quiet, smooth and effortless tripod movement on studio floors. All wheel castors utilize non-marking, non-setting polyurethane tires mounted on stainless steel rims rotating on needle bearings. Each wheel has positive locking in both radial & axial rotation with step-on step-off design. Each dolly leg folds from a carrying position to 120-degree lock position.