Evapolar Evaporative Cartridge is the part of evaCHILL Air Cooler & Humidifier, which needs to be replaced every 3-4 month to keep evaCHILLs cooling capacity. evaCHILL Air Cooler provides exceptional performance thanks to innovative evaporative material inside. The material is the compound of natural basalt fibers, which has huge evaporative surface and strong capillary effect, allowing evaCHILL to create the most energy efficient personal air cooler. The material filters out the dust from air, prevents mold and bacteria from growing inside while being eco-friendly and fully biodegradable. - For evaChill EV-500 only. Easy replacement every 3-4 months to save cooling power - Powered by evaBREEZE material 2.0 20% more nano-pores for more intense absorption and stronger cooling - 100% natural basalt fibers the evaBREEZE color may vary from white to gray or slightly yellow. - Long-lasting biodegradable material. Hypoallergenic, fragrance-free. - Cartridge material might slightly crumble during transportation. The basalt dust appearing, as a result, is harmless and can be wiped with a damp cloth.