This Mounting Solutions Plus Thumbsaver Magazine Loader provides a simple, easy-to-use magazine loading solution for high volume rimfire pistol shooters whose guns make use of a loading button style magazine. The durable plastic Thumbsaver enages the button on the magazine, allowing it to be fully depressed all at once by hand and rounds simply dropped in until loaded to full capacity. Compatible with single stack 22 Long Rifle Pistol Magazines incorporating a loading button, such as those used by Ruger Mark I, Mark II, Mark III and 22/45, Colt Woodsman and Hi Standard rimfire firearms.