MUV3 Nanalum Replacement FilterIf you are a avid wild camper you probably already own a water filter system these are replacement filters for the MUV series (can be combined with other MUV filters for extra filtering should you require it). The MUV3 uses the same technology developed by NASA as a way to reuse waste water on space stations. Nanalum utilizes electro absorption & is made with non woven highly engineered water filter paper impregnated with granular activated carbon.