Generally, it refers to switches with built-in mechanical locking function. When pressed down, the button will not fully pop up after being released, remaining in a locked state. It needs to be pressed again to fully unlock and pop up. After pressing the button, the switch will be locked in the on state through the internal mechanical structure; when pressed again, the locking structure is released, and the switch resets to the off state, maintaining circuit on/off without the need for continuous external force.