1) filter housing: 10"; 20"; big 10"; 20"; the inlet and outlet is standard designing. The material is ss and PVC. 2) color: white, blue, clear. 3) we can also including the relative filter cartridge. 4) filter cartridge as follows: A) PP (with or without PP spine) , the length is from 10" to 40 " B) wound string filter cartridge (PP spine and ss spine) , the length is from 10" to 40 " C) gac and udf or CTO. The length is from 10" to 20 " 4) PP pleated filter cartridge (0. 22 and 1 um) , the length is from 10" to 40 " D) resin filter cartridge, the length is from 10" to 20 ". 5) the ss filter housing is also multi-cartridges. From 3 to 100 cartridges, the length is from 10" to 40". 6) 2, 3, 4, 5 stage water purifiers.