All Sterilight UV systems include a quartz sleeve, which surrounds the lamp. The quartz sleeve provides thermal protection for the UV lamp and protects it from possible water damage. The quartz material used in R-Can's quartz sleeves are a 100% fused silica which lend to the sleeve's high transmittance. A high transmittance is important as the UV light must travel through the sleeve to get to the water. There are a variety of quartz sleeve designs, depending on the system that they are being used in.