The three pieces slide freely but lock securely. It will gauge a blade up to 12mm and a dado of 50mm (2").
results are close-fitting dados, but be sure to use test cuts first. The tool is aluminum with a smooth finish and well-defined edges.
If you enjoy gadgets, the HONGDUI JF06 gauge will keep you happy, as long as you get one that works properly.
Very quick learning curve to allow speedy and accurate half laps and dados.