How does the air pressure lever of Aofeng electric competition chair rise and fall?

There is a guard under the chair. Press it down to adjust the height. As shown in the figure below:

AutoFull proud electric competition chair, special electric competition chair for professional teams.

League of Legends professional league LPL2020 officially designated electric competition chair, sponsor of the 18th China International Digital Interactive Entertainment Exhibition (2020ChinaJoy), officially designated electric competition chair of Tencent Sport University E-sports League Challenge 2020, and officially designated electric competition chair of League of Legends Development League LPL2020.

Billie Billie 2020 World Electric Competition Chair Sponsor. Official sponsor of PDL Jedi Survival and Development Alliance. 2020CBEL City Online Health Competition officially designated electric competition chair. AutoFull proudly supports major e-sports clubs and becomes the official sponsor of professional teams such as RNG, Estar, Titan, Wolves, Tianba, RNG, Agirl, SMG, and the designated e-sports chair partner such as KA Women's E-sports Club.