The heaviest leather jacket I came across so far is not Yah-Ta Hey nor Langlitz. It is ‘Boss’ Double motorcycle jacket made by a small shop called Big Twin in Tokyo. They build their jacket from high grade vegetable tanned cowhide. It is apparently heavier and thicker than Yah-Ta Hey. I ordered a custom made jacket which is a copy of Vanson Suzuki Marauder jacket but it was so heavy and stiff that I never wore it at all.No, according to Dave Hansen, the former general manager of Langlitz Leathers , the Yah-Ta Hey jackets were made by Cal Leather.