This Swanson 4.5" Trim Square (Imperial) is a versatile and high-quality measuring tool made of durable aluminum alloy. It features a dual reference base, perfect for centering mortises and tenons, and a 3/8" drill guide for self-centering drill bits. The tool also includes a high-grade aluminum alloy construction, anti-glare finish, and 22, 30, 45, and 67 markings for easy angle finding. Additionally, it has 1/4" spaced scribing notches and a diamond cutout for precision. This silver Speed Square is rust-resistant and made in the United States, making it a reliable addition to any toolkit.