This is a Ruger® 10/22® .22LR 25-round extended magazine made by Champion Range and Target.
Crafted from durable polymer with steel spring internals, these 25-round extended magazines are designed to offer maximum performance and capacity for your favorite Ruger rimfire rifles. Champion Range and Target specializes in offering top-quality magazines and accessories for shooting sports—ranging from magazines to loaders and trap shooting equipment. Combining enhanced design with an improved factory-style header, these Champion magazines are engineered to offer superior rapid-fire performance on the range and on the hunt.