These cartridges have a sediment filter at the top and a filter screen at the bottom & can be filled with GAC carbon or any filter media by simply by un-screwing the bottom end cap.
The top centre core sediment filter can be replaced, see product below.
The cartridge takes approximately 800g of GAC carbon to fill.
Suitable for all standard 20″ filter housings.
Dimensions are 508mm x 72mm