This reflex sight is a rechargeable pistol/rifle optic with the first ever magnetic charging cover. Simply drop the cover on top of the sight plugged in to a USB-C charging cable and your new sight will begin charging. The cover features a percentage battery display, so you know where your optic is at in it's battery life. The Osight itself also has a tri-color battery indicator letting you know when your sight needs charging which won't be often as it has a over a 70,000 hour battery life on the lowest brightness setting.