ZEV Technologies Extended Magazine basepads for Glock magazines are available in either black, red, gray, or FDE. Includes extended magazine spring. Easy to install and to remove for cleaning. Lightweight and durable. FeaturesAdds +5 capacity on 9mm Adds +4 capacity on .40 cal Fits standard capacity GLOCK 9mm & .40 magazines 3-piece design is easy to reassemble without damaging the mag body Additional power spring provided Notes:GLOCK magazine not includedNot compatible with restricted capacity GLOCK magazines Compatibility: Gen 1-3 Fits: G17C, G17L, G22, G22C, G24, G24C, G31, G31C, G34, G35 Gen 4 Fits: G17, G22, G31, G34, G35 Gen 5 Fits: G17, G22, G34 DISCLAIMER: This product is not manufactured, authorized, endorsed, or warranted by GLOCK. GLOCK does not warrant or represent that this product is compatible with GLOCK pistols.