Well-thought-out and practical: Simply place SQUARE-tool on the test plate in the desired position. Then press the valve toggle-switch, and SQUARE-tool is firmly held by vacuum. The testpiece is already optimally aligned when positioned on SQUARE-tool. The positioning aid is an option together with SQUARE-line or SQUARE-plus, SQUARE-control or SQUARE-master.
In particular when calibrating knife-edge squares with our calibration set, the positioning aid SQUARE-tool facilitates the process.