https://www.fujischelevator.com/products/elevator-hydraulic-buffer.html An hydraulic buffer elevator is a safety device installed in elevator systems that absorbs hydraulic pressure surges that may be caused by sudden stopping or starting of the elevator car during operation. It is typically installed in the elevator pit, beneath the elevator car, and consists of a piston, cylinder, and hydraulic oil. When the elevator car experiences sudden acceleration or deceleration, the hydraulic buffer will compress or expand, absorbing the excess energy in the hydraulic system and slowing down the movement of the elevator car. The buffer in elevator is designed to operate automatically, without the need for human intervention, to ensure the passengers' safety in the event of an emergency. It is an essential component of elevator systems, providing a reliable and efficient way to control the elevator's speed and protect passengers' safety.