Shield Arms has a new extended magazine option. The S20 is a 20-round mag for the Glock 43X and 48 family of Slimline pistols. This could be a handy spare magazine for shooters already set up in the Shield Arms magazine system.Shield Arms @ TFB:[SHOT 2025] Shield Arms Revolver Optic Conversion (R.O.C.)Lawsuit Alert: Palmetto State Armory v. Shield ArmsShield Arms Drops the New Gen 2 S15 Ambidextrous MagazineShield Arms Releases Junk Sack Concealed Carry Fanny PackShield Arms Now Shipping The S15 Magazine +2 ExtensionThe S15 magazine needs little introduction and has become almost standard for G43X/48 shooters. Glock recently released its own 15-round magazines as well. But shooters who already have the steel magazine catch for use with the Shield mags can benefit from this new mag option. It has the same geometry and structure as the standard S15, but has been stretched to add five more rounds of capacity. It also has overinsertion tabs to keep it from being driven into the gun too far during enthusiastic mag changes.The S20 magazine is available for purchase now at an introductory price of $34.99. All images from Shield Arms. From the manufacturer:“The Shield Arms S20 is a patented 20-round steel magazine for the Glock 43X and Glock 48. Built on the same staggered-geometry platform as the S15, the S20 pushes capacity even further, giving you 20 rounds with no extension and no baseplate swap. The added capacity extends slightly below the grip frame, making the S20 the ideal high-round-count backup magazine rather than a flush-fit carry mag. Integrated over-insertion tabs stamped into the steel body prevent the magazine from being seated too far into the magwell, protecting feed lip alignment and reliability.The Shield Arms S20 takes the patented staggered magazine geometry that made the S15 the standard for slim-frame Glocks and extends it to 20 rounds—in a single steel body, not a mag-plus-extension assembly. Where the S15 gives 43X/48 owners a flush-fit carry mag with 50% more capacity than OEM, the S20 is built for a different job: a spare magazine with a higher round count, ready to ride in a pocket, mag pouch, or bag. Every S20 is machined and formed from steel and finished with the same QPQ nitrocarburizing treatment used across the S-Series lineup for hardness, wear resistance, and corrosion protection. The body also features integrated over-insertion tabs, stamped directly into the steel, that stop the magazine from seating too far into the magwell—protecting feed lip alignment and guarding against over-insertion malfunctions under stress.”