You can choose if you want to have Flow rate based on a mechanical davice (High Flow) or by pressure (MPS)
To choose an MPS you need roughly an idea how much flow you can produce with your system. The value after the mps stands for the maximum flow rate the device can handle.
mps flow 100: Range approximately 20 - 100 liters per hour / 5 - 26 US liquid gallons per hour (Art. 53130)
mps flow 200: Range approximately 40 - 200 liters per hour / 11 - 53 US liquid gallons per hour (Art. 53131)
mps flow 400: Range approximately 80 - 400 liters per hour / 21 - 106 US liquid gallons per hour (Art. 53132)
The USB HIgh Flow is a standalone device, the other one needs an AE (v3 up to v6), a Poweradjust or an Aquastream to work.