The Spinfire fast charger charges an empty battery in 3-4 hours whereas the standard charger takes 11 hours. This is a great accessory for your Spinfire Pro 2 if under heavy use and you want your machine at optimum performance. The maximum speed available will slowly trickle down as the battery flattens, therefore it is recommended to keep your machine as fully-charged as possible.
You can also plug this fast charger into the machine while it is being used and it will pump charge into the machine at a faster rate than it is being drawn. This means your machine will never run out of battery (almost the same as working off electricity).