Features: brand new and high quality High-quality Material :The for gap gauges are made of aluminum alloy & brass, and the surface is anodized, durable and compact. Do not worry about the ruler will oxidize and rust. Easy to Measure: Joint size can be accurately determined without tedious measurements. This tool can quickly measure the thickness of a material or the internal dimensions of a joint. Simply put one end of the woodworking ruler into the for gap, slide the woodworking ruler to fill the for gap, and then tighten the knob to accurately read the length of the for gap. Both inside and outside diameters can be measured. The measuring range is 5-40mm, which can almost meet your all requirement. Professional Design: Providing extreme cutting accuracy, accurate scale, exquisite workmanship, high precision. When you use one end to measure, the other end is also the same value. woodworker enthusiasts, designers, engineers, architects, students, teachers deserve it. Portability: Small and exquisite, easy to carry and store. You can put the ruler in your pocket and take it out anywhere to measure, when you need to perform clearance measurement work. One you cannot miss the sizing tool for ordinary woodworking seams. Application: Suit for many kinds of woodworking tools. Whether table-saw, bevel-saw, cantilever-saw, push-saw, engraving table or other tools to cut slots, it can be used to adjust the required slot size. Specifications: Material: Aluminum Alloy + Brass Size: approx 75x30x13mm/2.95x1.18x0.51 inches Package Includes: 1x Woodworking for Gap Gauge note: 1.Please allow 1-3cm errors due to manual measurement, make sure that you do not mind before you order. 2.Due to the difference between different monitors, the picture may not reflect the actual color of the item.