My chain tool is broken. Its a fatigue failure, the crack started at the top surface of the broken piece and propogated down, taking a chunk of metal with it. I got it second hand from a person in the club. It has no brand name but the "Made in Taiwan" is more than sufficient evidence for me. The chain pushing against that piece caused a lot of stress, besides the sharp inside edges probably also created a stress riser. Poor manufacturing.. ? Seems to me as if this tool was made using powder metellurgy, looking at the inside cleavage and the grains, if so perhaps it was not heat treated enough I think.