Fotga DP500 IIS 15mm Rod Rail Rig with Cheese Baseplate and Lens Support 15mm Rod Clamp for Follow Focus Matte Box Film Photography Canon Nikon Sony Pentax Fujifilm Olympus Dslr Cameras It consists of a bottom cheese baseplate,a top baseplate and 2 pieces 15mm diameter rods(Length:10"/250mm),a 15mm rod clamp for lens support The bottom baseplate and top camera mount baseplate are mounted on the 15mm diameter rod by seperate railblock,which makes them able to work independently There are 11 1/4"-20 screw hole and 2 3/8"-16 screw holes in the cheese plate The top camera mount baseplate can be easily mounted and detached by the quick-release railblock Made of aluminum,smooth and durable