Bergen BER3163 Pro universal Tension Gauge for Cam belts. This tension gauge is for adjusting the tension on drive belts on various serpentine and camshaft belt thickness. Adjustable dual scale graduations readable from front and back of tool. knurled aluminium rotator. Smooth rolling screw action. Readable from front and back of tool. Read in Nm. Length (approx): 85mm - 100mm. Width: 80mm.