I found little about the Durable company. Brando's leather jacket in The Wild Ones is thought by some to be made by Durable. They were a Canadian brand. If you have any information on the company post it, I would be interested. I did find information on the Lang Tanning company. The Lang Tanning Company then went on to become the largest sole leather producer in the British Empire, and Reinhold Lang, who was also a member of the Berlin Council in 1859, became a prominent local citizen. During the First World War, Lang Tanning produced huge amounts of saddle material, and in the Second World War it supplied sole leather and leather linings for aircraft gasoline tanks. The company discontinued operations as a tannery in 1954 due to competition from synthetic materials If this was the last leather they produced it would be made in 1954. I don't know how to date Lightening zippers. I will write Ken Calder, he may have an estimate. Again if you have any information on this zipper let me know. I thank Dave Sheeley for tipping on this beauty. Way too small for fit pics. I would estimate a size 36/38. Dave thought the jacket could be from the 40s. I called it a Cafe Racer because of the cossack collar. I have no idea what it would be considered other than extremely cool! It is a very nice Blue/Grey and in excellent condition through out. The two button cuffs say 40s to me. Check out this back.