1A 20mm magnetic block covered with a plastic protective sheet can be used to secure the saw and protect the cutting guide. 2 The dovetail guide gauge is made of aluminum alloy and brass, which is durable and is a woodworking art product. 3 Aluminum alloy dovetail guide gauge is suitable for all kinds of backless saws. The 4 Dovetail Rail Gauge is ideal for woodworking DIY jobs as it comes in 5 universal scales for you to choose from. 5This woodworking tool can provide you with an amazing experience as it makes small tail cuts easy, accurate and time-saving. Condition: Item Type: Dovetail Guide Gauge Material: Aluminum Alloy + Brass Color: Black Yellow Magnet Diameter: Approx. 20mm / 0.8in Clamping Material Thickness Range: Approx. 5-26mm / 0.2-1in optional types: 1:4, 1:6, 1:7, 1:8, 90 1 x dovetail guide rail gauge 2 x protective film