These 1/2" x 1-1/2" square machine keys are made of high-quality 18-8 stainless steel, ensuring durability and strength. The keys are 12 inches in length and have a rail height of 1 1/2 inches. This set includes three pieces and is perfect for various industrial applications. The brand is Midwest Fastener, a trusted name in the fastener industry. These keys are designed to fit into 2-inch diameter holes and are an excellent choice for securing bolts and nuts.