A 25 round magazine for Ruger 10/22 rifles and carbines. This magazine has a one-piece injection-molded housing which allows you to completely disassemble the magazine for cleaning and maintenance. This magazine also has a replaceable nylon feed lip insert with patent pending feed control spring. The feed control spring eliminates rim lock and other feeding issues associated with high capacity rimfire magazines. If you're looking for a durable and reliable magazine for your rifle or carbine, then purchase this ProMag magazine!