A ski goggle with a digital sound playing system, a ski theme park and a ski slope having specially designed music transmitted over each slope. In a first position for the actuation rod and the at least one wedge block, the first outer race and the inner race are non-rotatably connected. A container mounted in the tank includes an inlet for introducing liquid from the tank into the container and an outlet formed below the inlet. Two second rolling devices are mounted respectively on the sidewalls above the track plates and near the rear of the support to contact the slide body. The network device can then select a coding rate for the new communication session based on the determined weighted average.