An elevator buffer is a safety device located at the bottom of the elevator shaft (pit) designed to absorb the kinetic energy of the car or counterweight in the event of an overtravel beyond the lowest terminal landing. There are two main types: oil (hydraulic) buffers, used for elevators with rated speeds above 1 m/s, and spring buffers, used for lower-speed installations. Buffers are mandatory components under EN 81-20 and other international elevator safety standards.