The corner square is designed for those who run repeatable projects where datum doesn't change. With a recessed corner, this also supports Z probing for materials over 5.5mm thickness. Machined from aluminum and anodized black the square and guides will keep your projects straight. A great addition if using the GatorTooth Clamps, Threaded Inserts, or the T-Track Kit. These can be used with either M6 or 1/4 Hardware.