There are two switches, which can be used to reverse tires and brake discs, both of which are used to cool down. When going downhill, spray water on the brake hub and drive normally. Generally, tires are sprayed. There are two switches in the truck cab, which can be controlled by hand. In addition, the water spray is air-capped, and the nozzle effect is very good. Don't slide on the highway with water. Many trucks in Jianmenguan-Deyang section of Sichuan often have accidents when sprinkling water, especially when the temperature is low in winter, and the water sprayed by trucks in Qinling section of Shaanxi Province also freezes in winter.