The purpose of the dry sample filter is to allow our customers the opportunity to touch and feel the filter. Simply by moistening the dry practice filter under a water faucet and shaking out the excess, you will be able to feel what the moist Xcaper Emergency Mask feels like when it comes out of the vacuumed seal foil bag in an emergency. Mouth breathing is the best way to practice because that is how you will breathe when in an emergency. In a real emergency, your breathing rate will also be accelerated.