The Aeropress works in a similar way to a French Press. Made of food-safe plastic the Aeropress acts as a big syringe. Water and coffee to go into the lower chamber. A paper filter is placed in the cap. Then after 30-45 seconds of brewing time, the plunger is pushed down and this forces the water through the coffee and the paper filter resulting in a very smooth, full flavoured brew.
 
Buy refill paper filters here