Fill the OUTER [RE]FILL at selected source. Make sure NOT to fill past the indicated fill line. Utilizing your body weight for mechanical advantage, press with steady downward force. Press on the ground, or below or below knee level.
PRO TIP – Keeping the Cap “on” while pressing creates a comfortable pressing surface which reduces hand discomfort or fatigue (especially when doing multiple presses). Venting the cap (loosening a 1/4 turn) allows air to pass through while purifying.