At your request we are please to offer the Bestwater cartridge for the LONDINIUM I in both medium and large sizes and a 20% discount when purchased in multiples of six (one box)
The large size has twice the treatment capacity of the medium size, which is needed in areas like London where the water is very hard and so the number of litres treated by the medium size cartridge is greatly reduced from the 100 litre rating based on a water hardness of around 150mg/L from memory (cf London which can be around 320mg/L and so you are changing the filter every 3 weeks)