ULTRA THIN multi-layer UV filter that reduces the risk of vignetting - EVERCLEAR 5 treatment. The EVERCLEAR 5 coating makes a program out of its name. The 5 stands for the five advantages of this coating: water repellent, oil repellent, dust repellent, dirt repellent and scratch resistant. An ultra-thin design results in a very low weight. (e.g. the 77mm UV Prue Harmonie - 10g) The filter reduces the atmospheric "haze" effect associated with UV rays and provides your front lens with protection from dust and scratches - Made from very high quality materials without compromise.