jons commentsthis water bladder is a whopping 3 liters which goes into the trail-9 and trail-18 backpacks.3 is about the capacity that you need to get through a full day in the tropical heat. it also leaves room for you to throw your bladder in the freezer and still have enough liquid when it all that godly ice melts. remember that water expands when frozen, so those little one-liter bags are no good for ice mixing.kriega also sells parts separately for this bladder, so it is possible to do routine replacements of the mouthpiece. they are not on our website, but we can get them.the sales stuffthe kriega hydrapak heavy duty, military grade reservoir and insulated drink tube is compatible with kriega trail 9 and trail 18 adventure backpacks.the 'first wave' (military spec.) reservoir is designed for extreme environments. the 0.4mm thick thermo polyurethane (tpu) is twice the thickness of the standard consumer model. fully reversible for easy cleaning / drying. a wide slide-seal™ top makes it easy to fill and creates a leak-proof seal. the hydrofusion™ tube is durable and lightweight with built-in foam insulation, this simple, but breakthrough tube helps keep your water cooler in even the hottest temperatures.surge™ bite valve naturally ergonomic design with twist on/off function and protective cover. plug-n-play™ connect system lets you easily disconnect the drink tube (an auto shutoff valve prevents leaking) and remove the reservoir from your pack for convenient refilling while leaving the drink tube in position.featureswide slide seal™ for easy fillreverse to clean / drydishwasher safeincludes tube management for harness3-litre (126 fl oz) capacityreversible for easy clean/drywide fill (sliding seal)plug-n-play (dry-break)insulated drink-tubehook and loop tab - drink tube managementfda approved polyurethane