I picked up a new Source Aquasource 25L water tanker hydration carrier from Facebook Marketplace and I couldn't be more pleased with this tactical hydration carrier by Source Aquasource.
25 litres (6.6 gallons) is a fantastic capacity and a convenient way to store water in the event of an emergency, natural disaster or just a week of hiking and camping.
Source Tactical Universal Tube Adapter: https://amzn.to/2DRv1Rk
The only ones that I see on ebay (appear to be 20L and not 25L) are found here: https://ebay.to/2J2YwnL
Amazon has the CamelBak SqaudBak 25L here: https://amzn.to/2VgzkAx