All Pelican 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 Pelican 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.