Springer Precision 9/40 140mm extended capacity base pads are CNC machined from aluminum and hard anodized for a long service life. They are specifically designed to work with mag wells and fit the USPSA 140mm magazine gauge. The unique attachment design provides a low profile, sleek design that is very stable and easy to remove. We include a .050 hex driver that makes installation and removal a breeze. There will be a gap between the base pad and frame if used with a compact model. Adds 2-3 rounds.