BRoyal Berkey RB4x2-BB Water Filtration System w 2 Black Elements ReviewbP PP Royal Berkey RB4x2-BB Water Filtration System w 2 Black Elements PThe Royal Berkey RB4x2-BB has almost 50 more capacity than the Big Berkey (3.25 vs 2.25 gallons)PFully assembled system stands 23" in height with a diameter of 9.5".PThe upper chamber nests within the lower chamber for transport and stands only 15.25" in heightPThe Royal Berkey stores about 3.