A latching device for insertion into a tube provides two large flat buttons one on each side to lock the tube relative to an outer tube or to two parallel plates. A tubular housing with open ends slides into the tube between the side walls of the tube with the ends of the housing substantially butting inside surfaces of the side walls. The buttons are mounted on respective slide members mounted in the housing spring biased apart so that the buttons can be depressed. One or two set screws acting as stop members can be inserted after the housing is moved to the required location in the tube to prevent depression of the buttons to a position inward of the inner surface of the tube so that the housing is held in place.