This is a Manfrotto camera dolly. It allows for smooth dolly shots by placing a tripod on a cart with casters. - Type: Tripod accessory - Included: Instruction manual, tools - Color: Black I purchased this about 20 years ago when I was studying filmmaking. I used to mount tripods like Sachtler and Manfrotto on it and roll it around for moving shots. While it's a simpler version compared to a professional track dolly, it's easy to use and I think it's useful for creating stable images. You can switch between moving (up) and fixed (down) positions. When moving, it lifts slightly to allow the casters to function. An assembly instruction manual is included. There are red and yellow markings, and this function works by hooking the metal fittings. As a size guide, the central bar is about 70cm, and the two bars that attach to the center are about 57cm. Since it's handled at ground level, there are some scratches and dirt. There are also traces of tape. I hope you understand that this is a used item. I'm selling it due to moving and decluttering. Thank you. ※I don't have a suitable box on hand, so I will wrap it in bubble wrap for shipping.