●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.