Quartz is one of those few solid materials that are virtually transparent to short-wave ultraviolet. The glass quartz sleeve allows ultraviolet light to transmit into the water and sterilize it completely. Quartz sleeves ensure that there is no temperature fluctuation and helps to insulate the bulb from the low temperature of water, thus maintaining a higher UV output. Quartz sleeves protect the UV lamps from high water flow, temperature fluctuation and breakage.
Quartz sleeves are available in different lengths, thickness, diameter & either open ended. A sleeve makes periodic cleaning and bulb replacement easier.