Using this Bosch battery charger is easy. First, make sure your vacuum cleaner is turned off. Then, connect the charger to a power outlet with an input voltage between 100 - 240VAC. Next, plug the charger into your Bosch Readyy'y 20 - Volt rechargeable handheld vacuum cleaner. The charger will start supplying 22 volts DC at 350mAmp to charge the battery. Remember, this charger is only for Australian models BCHF220GAU/01, BCHF220GAU/03, and BCHF220GAU/04. If you're not sure if it fits your vacuum, ask us before buying. For maintenance, keep the charger in a dry and cool place. Avoid exposing it to water or extreme temperatures. Also, make sure to clean the charger's connectors occasionally to ensure a good connection. If you have any other questions, feel free to contact us.