Stick welding, also known as manual metal arc (MMA) welding, is a welding type that uses the welding rod in the welding tongs as the welding electrode. The arc is struck between a welding rod and the work piece. The difference from other welding methods is that the welding rod, which acts as the welding electrode in MMA welding, continuously shortens as the welding progresses. In TIG and MIG/MAG welding, the distance between the welding gun and the workpiece must be kept constant. However, in MMA welding, the welding tongs must be constantly moved towards the workpiece to maintain a constant distance between the welding rod and the molten weld. This presents special challenges for MMA welding.