Doulton ceramic and omnipure superblock twin under sink replacement water filter pack – special 9 inch size. Quality doulton cleanable silver impregnated ceramic sterasyl 0.9 micron absolute pre filter and 2nd stage 1 micron absolute omnipure super block carbon cartridge. With the Royal Doulton Superblock Twin Undersink replacement water filter pack your family will be guaranteed micro-biologically safe drinking water all year round. Size 9 inch x 2.5 inch cartridges. These filters will remove – chlorine, heavy metals, lead, copper, bad taste and odours, dirt and sediment, herbicides, pesticides, volatile organic compounds, bacteria, giardia, cryptosporidium, cysts, ecoli and more. Flow rate 2 – 3 litres a minute. NSF certfied. Please note the 9 inch size is for other brands of systems that take the uncommon 9 inch cartridges, if you have purchased the system from us originally you will require 10 inch cartridges.