WFM-005 Ceramic Compatible with Doulton Supercarb/Ultracarb fits HIP, HIS and DUO Short MountUSAGE: Compatible with Doulton Supercarb Ultracarb 18 20mm thread Please note that the short mount cartridges measure 20mm, you can check your current cartridge by measuring the threaded section at the top of the cartridge. The WFM 005 will fit a number of systems including HIP, HIS and DUO. Our cartridge will effectively remove common impurities such as chlorine and dissolved organics to leave fresh, refreshing water dispensed from your triflow tap.