Honeywell, Siemens and Johnson are the best brands (in order). Siemens acquired the building control of Langille in 1990s, and now it is called apogee system. Johnson's company bought the products of a small factory in the United States and brought them to China to fight the price war. The quality is much worse than the first two. Honeywell's Alerton, Zhuo Ling and Webs are all good products, and Alerton still has advantages in function and stability. Alerton is also a product acquired by Honeywell, and its market share in the United States is definitely 1, but as far as I know, its market share in China is slightly poor, but it is really a good thing.