lincoln electric square wave tig 200 tig welder, k5126-1 lincoln electric the square wave tig 200 is a portable tig and stick welding machine that lets hobbyists, makers, small fabricators and craftsmen explore their creativity.it is designed to help expand your welding expertise. as your skills and confidence grow, you can take advantage of the square wave tig 200’s additional functionality. no matter your skill level, you won’t be disappointed.