Leupold Quick-Release (tm) system. Consists of one piece base and 1" low rings in matte blue. This is for a Winchester Model 70 long action. The base is marked "70 MAG" on the bottom of the base. This setup was originally on my Model 70 in .375 H&H. This allows you to quickly remove the scope and use the iron sights if need be. I bought the rifle at a gun show and promptly removed these rings and bases.
This setup is $105.90 in Brownells. $85 you pay shippping.