Fits .177, .22, .25 & .30 caliber FX Wildcat standard magazines. Felt and audible click when inserted so you know your magazine is held securely. This system attatches to the magazine's ball bearing housing so it can rotate for quick and simple reloading. You can easily reload with one hand! The days of carrying your extra mags in your pocket are over, keep them within arms reach and easily accessible. The FX Wildcat mag holder system helps prevent pocket dust/debris from collecting on the pellets while stored. Made from lightweight 6061 T6 aluminum and anodized black with a superior coating, these guys will follow you through the muck!