There is no need to clamp urgently it has a fixing device. Drill locator guide with quick gripper for quick and tight clamping. The hinge light fixture is made of aluminum alloy body not rusty light and strong. Chip removal fixture chip removal is larger faster and smoother drilling is more labor-saving and work efficiency is improved. Bottom size: 12 x 5.3cm / 4.72 x 2.09in Clamping board thickness: 15-25mm/0.59-0.98in Hole specification: 35mm / 1.38in Margin adjustment range: 3-7mm/0.12x0.28in Note: Random color don t accept the specified color. Material: Aluminum alloy colour: silver + black Package Contents: 1 x Woodworking Hole Drilling Guide Locator(Some accessories have random colors) Only the above package content other products are not included. Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.