If you need an extra USB plug for your batteries, you will find it here. Charge the battery by inserting it into the USB. Use the USB together with our adapter or directly in a computer. The diode on the USB will flash red, when insert correctly. Charging time for a fully discharged battery is approx. 4 hours with the USB in a computer. For faster charging, we recommend to use our Adaptor, where charging time is only 2.5 hours. Please notice that the adaptor is sold separately, this is only the USB plug. During charging the diode on the USB is red, when the diode turns green, the battery is fully charged. With the smart thread-system, a new filter is easily attached to the battery. Are you a new customer recommends we to buy a starter kit, consisting of 5 filters, battery, USB and adaptor.