A Labor tool widely used in railway track overhaul and maintenance. Because it is also in the game 《 half Life it appeared in the series and was used freely by the protagonist Gordon Freeman, so it was also called by netizens" sword of physics", or the origin stick. Wrecking bar is to use the lever principle to make heavy objects overcome gravity and lift heavy objects from the ground and move them. Wrecking bar is divided into hexagonal stick, pole and flat pry. Hexagonal stick and pole can be processed as: two ends round, two ends flat or one end round and one end flat, as building tools or hardware tools, the latter can be used for basic hand tool of automobiles. Flat pry is the difference between length and thickness, most of which are used as tire repair kit.