In order to avoid the gaps between the boards due to the tightening of the nut and the tightening of the top and the loosening of the bottom , we have developed the design of the top thin and bottom thick fixing block to achieve bonding of boards Such as cabinets or boxes , drawers , birdhouse , mailbox , picture frames and shelves Holds square while glues is drying or fixing Positioning squares featuring a high-impact ABS construction that insures durability and lightweight It ' ll be breezed to create the precisions 90 degree woodwork Quickly and easily clamp on the squares Including 3-inch and 4-inch sizes , great for working with framed woodwork projects of different sizes, Manufacturer: Watreketal