This is an SNS binding mounting jig designed to provide a drill pattern for mounting Salomon cross country bindings. Salomon claims that all their products have the same screw location, so this jig should work with both SNS and Prolink. It can be used both to mark the screw hole positions only (freehand drilling), but it is more convenient to use the jig as a guide for your drill head.
Method of use: Place masking tape on the top of your skis (optional / you can draw directly on the ski), find your balance point and mark that line. Draw a center line (optional - the centering jig is easy by eye) and secure a jig using clamps or tape carefully. Find a 3.5mm drill and mark the required depth of the holes from the tip using tape. The depth is the length of the threaded part of the screw plus 5 mm for the thickness of the jig. Place it in a drill chuck. Drill all 5 holes.