501 and 550. I like the 550 much better then these mostly because of the heavier material but 501's have always been my go to jeans to work around in. Also the 550 have a more relaxed feel in them.
These jeans are one of the only kinds that my husband will wear. The fabric lasts much longer and most other jeans being sold. They are also one of the few brands of jeans that really fit him will. He prefers the button fronts to the zippers.