Recommended pre-filter brands are: Honeywell, 3M, Midea, Qinyuan, and A.O. Smith.

1. Honeywell

Fortune 100 company, the world's largest supplier of building products, and one of the 20 most admired high-tech companies ranked by American Fortune magazine One of the top ten brands of pre-filters, Honeywell (China) Co., Ltd.

2. 3M

A diversified multinational enterprise with a long history, a world-famous automotive supplies brand, a global diversified high-tech enterprise, one of the top ten most respected enterprises, and the world's most One of the top 50 performers, 3M China Co., Ltd.

3. Midea

One of the 500 most valuable brands in the world, the largest white goods production base and export base in China, the most valuable brand in the country, the top 100 enterprises in Guangdong, China The largest 500 companies, well-known trademarks in China, Guangdong Midea Group Co., Ltd.

4. Qinyuan

National key new product, Chinese famous brand, Chinese well-known trademark, 95 National Technological Innovation Outstanding New Product, National Key Torch Plan Project, National High-tech Enterprise , Ningbo Qinyuan Group Co., Ltd.

5. A.O. Smith

Founded in 1874, American hot water expert, advocate of home central hot water supply system, leading water heater manufacturer, A.O. Smith (China ) WATER HEATERS LIMITED.

Reference for the above content: Baidu Encyclopedia-A.O. Smith