Amzdeal 7 inch Professional Tabletop Dolly Skater Magic Arm for Digital SLR Cameras Video Camcorders There are 3 1/4" holes on the plate,which makes you able to install your camera forward, middle, or backward. High quality durable and sealed bearings on both sides of each wheel Hard coated polyurethane wheels. Engineered to have scaled adjustments to make precise shot sequences and precise adjustments to the shooting process With 1/4" adapter screw thread to connect to your camera, ballhead, magic arm etc. Main body is made of metal, sturdy enough to carry you DC and DSLR cameras. Precision extruded industrial grade anodized aluminum construction