In addition to formaldehyde companies in Hangzhou, who can guarantee for ten years?

Ten-year warranty? It has been 20 years since my home, and formaldehyde has been completely removed. The 10 project spray I used at the beginning is easy to realize. Now only small companies will say that there is a warranty for several years. Anyway, formaldehyde hasn't been removed since I used this spray. Just go to Taobao to buy it. That's great.