Tension locks GN 831 are used for securely holding flaps, container lids and the like. Due to the dead centre exceedance, they keep vibration-resistant. Using the lifting path w1 of the tension hook, the parts to be connected can be pulled together up to 5 mm when tensioning. The adjustment range w2 is achieved via a spindle M5 of the tension hook. To attach these clamping clasps, screws with low head height are to be used, such as cylinder screws with hexagon socket DIN 6912. The stated holding force is a guideline for the possible static tensile stress of the clamping lock. Depending on the operating conditions, e.g. due to vibrations or impacting stress, the holding force may be impaired. The counter hook is included