Built to fit the Quick-Release (QR) mounting system, these QR Rings allow for a scope to be removed and mounted quickly, without losing any accuracy. Extension Rings allow you to shorten or lengthen your ring spacing on rifles. A common application is on firearms with long actions, where the normal 4" ring spacing is inadequate. But whether you are lengthening or shortening the ring spacing, our extension rings allow you 5/8-inch of adjustment. Extension Rings mount on the front and rear of QR bases and are available for 1" main tubes. Matte finish. Per 2. Made in USA. Available: Low, Medium or High rings and Medium or High extension rings.