Includes two Stair Gauges. Turn any Square into a Martinez Square with the ?Simple Easy Stair Gauge?. Fits any square with varying thickness?s, with an adjustable opening, ranging from 0- 5/16ths. The challenging work to adjust your stair gauge has been simplified with a hard anodized cam lock. Once set to your ?go to? square, the cam lock allows for simple adjustments to be done with one hand.