Replacement O-ring set, part 180007-0038-01, for Hanovia medium-pressure ultraviolet disinfection systems built around the 38 mm quartz sleeve. It supplies the O-rings disturbed when the sleeve is withdrawn for cleaning or replacement, which are single-use items and should not be refitted. The 0038 suffix is the sleeve diameter in millimetres; systems using the 47 mm sleeve take set 180007-0047 instead. Reference number 2203-1205.