Add Additional Roundds Without Special Tools
High-strength, aircraft aluminum base pad slides open to accept
magazine body and locks into place. Removes in seconds for easy
cleaning. Base pad increases capacity of 15 round, .40S&W
magazines by three rounds and 9mm magazines by 4 rounds.
Maintains 140mm USPSA rule and increases magazine to maximum
levels for competition. Comes with extra-power, steel spring and
Big Book Catalog, Issue:65, Page:208
SPECS: Aluminum, black. Steel mag spring. Fits small frame
Glock 9mm & .40 S&W pistols.