Welcome，Please read the following instructions。Features:100% Brand new and high quality!Positive locking knobs assure rock-steady focus.If you purchase two Piece macro sliders， they can be combined into a 4-direction macro slider. And it can also be divided into two one-way macro slider， it is very simple to mix and split.Suitable for: All DSLR or DC with standard 1/4'' screw hole.Specifications:Material: MetalColor: BlackLength: 156mm， Width: 93mm， Height: 20mmPackage includes:1 x Two-way Macro Shot Focusing Focus Rail SliderMy Store Provided Intimate Service.