Don't nock it till you try this! Our Aluminum Bow Square is the perfect tool for all your string tuning and nock placement needs. Accurately check string brace height, or precision set your nocking point. Measures 6-12" for brace height, and up to 5/8" height for nock point setting. Solid aluminum construction makes it a sturdy addition to your bow building and arrow crafting toolbox. Color may vary.