The secret to the compact functionality of the Woodpeckers Box Clamp is it's tapered wedge design, (only one moving part), that simultaneously pushes the mating materials down and in with less then two turns of the screw while applying an enormous amount of clamping force. Just one Box Clamp can save you time and aggravation as it instantly squares up your box sides and holds them in place for gluing, screwing or nailing.(2 clamps are recommended for larger panels)  Accomodates assembly of 2 different panel thickneses (up to 1/4 difference). Machined from a solid aluminum billet for perfect alignment. Can be used as part of a clamping fixture or un-fixtured for large cumbersome projects.  The unique space-saving design of this box clamp gives you more surface area then most other corner clamps while doing away with protruding handles, etc. The Box Clamp was designed to take up the least amount of space while offering more, dead-true clamping surface then other comparable clamps. Each Woodpecker 4” Box Clamp is made in the U.S.A. and guaranteed for life. Box clamps are sold individually.  Each order is for a single box clamp.