Only for use with the M1 and A2 KIKI Pure Air Purifiers. Our KIKI Pure M1/A2 HEPA filters are designed to last between three and six months. How often you replace them will depend on how frequently you use your device. We recommend changing the filter every three months if you use it daily to ensure your device is working at peak performance. GUARANTEED 30-DAY MONEY BACK RETURN and 1 year limited warranty plus online customer service. KIKI Pure M1 HEPA filters are engineered to endure for three to six months. The frequency of replacement depends on your device's usage. For daily use, we advise changing the filter every three months to maintain optimal performance.