Do you need ultimate protection while retaining lightning fast access? Don't fumble around trying to unzip a pouch, or open a clip, simply give a quick tug and you are using your device a second later. For use with the 5700 series or similar sized Kestrel wind meter, features a MRD (Magazine Retention Device) which is adjustable for the desired amount of retention on the device. A 1/8" Allen wrench in needed to adjust the set screw allowing for incremental adjustments of the MRD.