These Redfield See-Thru Dovetail Rings are designed to provide a rock-solid mounting base for your favorite riflescope while also allowing you to continue to use your iron sights. This particular set of rings is designed for use with a 3/8-inch grooved receiver.If you are looking for a set of high-quality and durable see-thru mounting rings look no further. This set of rings was machined from aircraft-grade aluminum to ensure a lifetime of durability while being lightweight enough that it won't weigh you down. What more could you ask for in a mounting set?