Quartz sleeve for the Hanovia UV1000 and UVS 2.5 disinfection systems, 728 mm long — one sleeve serving both models. 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. This catalogue also lists a 728 mm UV1000 sleeve under reference 2298-1012; if you are ordering for a UV1000 rather than a UVS 2.5, check both listings against your parts list before ordering. Reference number 2264-0908.