This is a push vice to center your work on your CNC bed. It prevents the work from moving sideways. Solid infill is recommended. If you plan to use this for heavy duty, you should use the metal version instead of plastic. When open, the vice is a cube. When closed, the top section moves against the work and secures it on that side. If you want to secure a square sheet of metal, you should use 4 such vices, one vice for each side of the square. This version uses a M5 screw/washer/nut to bolt the vice to your CNC bed. It has 5mm of travel against the secured work.Bolt a M5 screw to your T-Slot CNC bed. Slide the bottom of the vice in. Slide the top of the vice in. Slide a M5 washer in. Run a M5 nut at the end of the screw. Place the vice near your work, touching it. Tighten the M5 nut until your work is secured.