The quartz module is the sleeve assembly supplied as a complete unit rather than as a bare tube — sleeve, seals and end fittings together, ready to fit. Ordering the module rather than the loose sleeve removes the two things that most often go wrong at a sleeve change: a seal reused past its compression set, and a sleeve loaded unevenly at assembly. This is the 1224 mm module for the WLR20. The matching lamp is stocked under item 13110-0509. Wedeco was founded in Herford, Germany in 1976 and is now a Xylem brand.