Ruger 90273 4B30 Scope Ring Matte Black 30mm Medium
http://www.tandktactical.com/shop/736676902736-ruger-90273-4b30-scope-ring-matte-black-30mm-medium-7872
http://www.tandktactical.com/web/image/product.template/7872/image_1920?unique=f8253a1
Designed to fit a scope with a 30mm scope tube diameter and a 42 MM objective diameter.
