McGill Extension Ring Square provides a durable solution for electrical box extensions and installations. Measuring 4-11/16" x 4-11/16" x 2-1/8", this gauge 16 ring accommodates standard square electrical boxes, making it ideal for surface-mounted wiring applications and box extensions. Built to McGill's quality standards, it ensures secure and reliable connections for residential and commercial electrical work. Perfect for electricians and contractors requiring dependable extension hardware.