Emergency hand actuator

From Memory Alpha, the free Star Trek reference

Emergency hand actuators are small devices used to open doors aboard Starfleet vessels in the event of power loss. They are stored at convenient locations near turbolifts, Jefferies tubes, and other vital areas. Use of the device involves attaching it to either side of the door, then pulling the door open. (TNG: "Disaster", "Starship Mine"; VOY: "Year of Hell")