"Cartridge Filter Kits Compatible with sleep equipment Cleaner Machine. Please Note: This cartridge filter kit is a generic product Produced and Supplied by WUYUAN! PREVENT WATER LEAKAGE The check valve is made in diaphragm structure which could better prevent water backflow and leakage. EFFICIENT CLEANING: The replacement cartridge filter kit compatible with sleep machine cleaner. The check valve helps keep water away from the machine. EASY INSTALLATION Removing the old filter and replacing with the new cartridge filter kit compatible with cleaner machine, no need to disassemble the unit. One Set Filter Kit includes: 1 PCS Cartridge Filter and 1 PCS Check Valve RECOMMENDED 6 MONTH REPLACEMENT: To ensure optimum protection and effectiveness of your cleaner machine, it is advised to replace the filter cartridge every 6 months. "