Yongyi safety valve: Although it is not a professional safety valve, the word-of-mouth for so many years proves that this brand is more reliable and the price is relatively old;
Baoyi safety valve: it is a professional safety valve with brand guarantee, and the price is ok compared with the above two, which is relatively high quality and low price;
Tianhe safety valve: a professional manufacturer of safety valves, also an old brand, has a good reputation. The price is reasonable and the quality is worthy of the name.
The above companies are basically specialized in safety valves, and they are all guaranteed. In terms of price, it should be from high to low.