These parallel guides are perfect for straight cutting using circular saws, jigsaws and routers over a 50" distance. A quick-release sliding mechanism allows for one-handed use and ensures a positive lock when in the correct placement. This particular clamp guide will clamp across a 4ft board, with a maximum clamping width of 1270mm. Includes: 1x 1270mm Clamp Guide Integrated quick-release lever for rapid lock/unlock One-handed sliding lock 1270mm Max clamping width Robust construction.