Using this Lezyne Femto USB Rear Light is easy. First, attach it to your bike using the mounting strap which can fit different bar sizes. You can then choose from five output modes according to your needs. When the battery runs low, simply use any Micro - USB cable to charge it, and it can last up to 15 hours. As for maintenance, since it has an IPX7 water - resistance rating, it can withstand wet conditions, but it's still a good idea to dry it after getting it wet. Also, check the threaded composite cover regularly to make sure the USB port is well - sealed.