A gauge (template) for checking the geometry of a saw chain: it helps check the depth gauge height, the pitch and the tooth size. Used when sharpening the chain so that the teeth stay uniform.
If the saw cuts unevenly or vibrates after sharpening, check the chain with the gauge. Choose the gauge to suit the chain pitch stated in the marking.
It is best to do the work on a cooled engine with the ignition off, and to tighten the fasteners without overtightening, so as not to strip the thread in the body.
