For HPA airsoft (and paintball) users looking for a tank pouch for the external HPA tanks can consider this Valken Tank Pouch the Kaiju presents in this video. It is a strong and durable nylon pouch that is designed to hold compressed air tanks up to 90 cubic inches or Co2 tanks up to 24 ounces. It attaches to MOLLE webbing or waist belt up to 2.5 inches wide in a vertical or horizontal position. Colour options are black, olive and tan.