1[20mm Diameter Design] Suitable for use on woodworking tables as a table limit block, providing stability and accuracy for woodworking projects. 2[Multi Function] Serve as a frame square attachment, stair gauge knob for circular saws, stairs layout guide, and for marking repetitive angles on carpenter square or guiding saw cuts at angles on carpentry squares. 3[Sturdy Construction] Crafted from CNC machined anodized aluminum alloy, this 20mm dog hole limit block is sturdy, rust and erosion resistant, built to last for long term use. 4[Steel Screw Adjustment] The stair gauge is equipped with an oxidized steel thumb screw for durability and slip resistance, ensuring ease of use. 5[Compact and Portable] This angle ruler auxiliary clamp is small in size and easy to carry, making it convenient for on the go woodworking tasks and projects. 1 x 20mm Dog Hole Limit Block