This is a Pentair ESO-2 emergency shut-off button. In the event of any emergency relating to a pool, hot tub, or spa these special emergency shut-off buttons are designed to be activated by anyone. Once pushed the spa pump, jet pump, and other water systems will shut down until the button is reset. Specific codes vary, but codes usually require these buttons when a hot tub is present. I do not recommend testing these buttons without permission in public when there is no emergency, please obtain special permission (like I had). Thank you for watching! Follow S.E.R. Safety on TikTok: https://www.tiktok.com/@s.e.r._safety?lang=en Follow S.E.R. Safety on Instagram: https://www.instagram.com/s.e.r._safety/?hl=en (@s.e.r._safety) & https://www.instagram.com/ser_safety_store/?hl=en This is my other channel, subscribe to see some wild wilderness adventures: https://www.youtube.com/channel/UCyA251kebpkxsnIZbG6lA0w Twitter: https://twitter.com/SER_Safety (@SER_Safety) #emergency #pooldesign #hottub