Using this Phaser3D 18650 Battery Casing is easy. Just open the screw - on lid and place two 18650 batteries inside. Then, screw the lid back on tightly to keep the batteries secure. When using, make sure not to over - tighten the lid to avoid damaging the casing. As for maintenance, keep it clean and dry. You can wipe it with a soft, dry cloth if it gets dirty. Store it in a cool and dry place when not in use. And always check the lid's tightness regularly to ensure the batteries stay in place.