Quartz sleeve for Hanovia medium-pressure ultraviolet disinfection systems, part 320001-1488, 1488 mm long — the length is carried in the part number itself. The quartz sleeve is the pressure barrier between the treated water and the lamp, and the only optical path between them, so it must both hold system pressure and pass UV without loss. Two points to check before ordering. This catalogue also carries sleeve 320004 at the same 1488 mm length; they are different parts and length alone will not tell them apart. And part 320001-1488 appears in this catalogue under a second reference, 2216-0206 — compare both entries before you order. Reference number 22146-0618.