Magazine extensions are a great way to give your gun more firepower, without adding an excessive amount of bulk. Machined from 6061 T6 Aluminum, Faxon Modular Magazine Extensions feature unique modularity that allows users to choose from a variety of colors, setups, and finishes for their Glock® 19 or Faxon FX-19 handgun. +5 combo kits include a +5 compatible spring, while +3 extensions are OEM spring compatible. Both kids come with assembly screws. All Faxon Modular Magazine Extensions are backed by the Faxon Lifetime Guarantee.