Includes one pair. The MTC Ballistic Nylon Stair Gauge is made from glass-filled ballistic nylon material. We used the same firearm material technology to create this rugged stair gauge-it’s tough and highly durable. Our design is built with a cam lock function that won’t mar your square’s surface. This unit fits any square with varying thicknesses, with an adjustable opening, ranging from 0- 5/16ths. Made in collaboration with our aluminum stair gauge as a durable, more-accessible option.