Fifteen stages, one housing.
Nothing in the cartridge is exotic. Every layer is a material that water treatment has used for decades, in the order that makes each one work.
What matters is the sequence, and that there is enough of each to last three months.
Cottonand mesh
A pad of PP cotton behind a stainless screen catches sediment, rust flakes and anything the pipes have shed on the way. It protects everything downstream from clogging early.
KDF-55
A copper-zinc alloy that works by redox — an electrochemical reaction that converts free chlorine into harmless chloride. Unlike carbon it keeps working in hot water, which is where most of a shower happens.
It also inhibits bacterial growth inside the housing between changes.
The heartof theproblem
Hard water carries dissolved minerals and chlorine straight onto your skin, every day, for as long as you've lived in the Southwest.
Calciumsulphite
A second pass at chlorine, effective across the full temperature range. Chlorine is the single thing most responsible for the tight, stripped feeling after a shower, so it gets treated twice.
Activatedcarbon
Coconut shell carbon, with an enormous internal surface area relative to its volume. It adsorbs organic compounds, odour and the residual taste of treatment chemicals.
Mineraland ceramic
Maifan stone, ceramic and mineral spheres give the water a final polish and a small mineral contribution before it reaches the head.
A second cotton pad closes the stack so nothing granular ever leaves the housing.
The numbers
Everything measurable about the filter, in one place.
Cartridge life varies with water hardness and household use. Hard water areas should expect to change more often.