The original, http://doultonusa.com/HTML%20pages/ceramic_candles_gravity.htm
Formerly Fairey Industries, The originally designed filters for the UK military.
How to make a two bucket gravity fed filter system using the Big Berkey/Berkefeld or other brand ceramic cartridges; https://www.instructables.com/DIY-Berkey-Water-Purifiier/
Plastic spigots can be had from ebay
Very nice. Thx for that link. ;-)