GM Ignition Key Blank Selection Guide / Key Bitting Depth Gauge

This item is a specialty automotive tool, specifically an ignition key blank selection guide or a key bitting depth gauge, likely used for GM (General Motors) vehicles. It is constructed from a flat piece of brushed or ground metal, likely stainless steel or hardened steel, giving it a light gray, almost silver, appearance with a matte finish. The overall shape is an elongated oval or a rounded rectangle with four distinct notches cut into the periphery, two on each of the shorter, flat sides. The central feature is a large circular cutout, surrounded by two concentric rings of smaller circular holes. The inner ring contains six holes, and the outer ring contains twelve holes, all of uniform size within their respective rings, suggesting precision manufacturing for measurement or alignment. Although no specific measurements are discernible, it appears to be hand-held size. There are minimal signs of wear, mostly light surface scratches consistent with use in a workshop environment, but no major damage, rust, or deformation. A faint, diamond-shaped logo or marking with the letters "GM" or a similar manufacturer's mark is partially visible on the left side, indicating its origin or intended use. The edges appear smooth and well-finished, suggesting good craftsmanship suitable for a durable tool. The inclusion of various taps and dies in the surrounding area implies that this tool is part of a larger set used for automotive lock or ignition system work, particularly for key cutting or decoding.