Levi's 501

The Levi's 501 is the button-fly, straight-leg jean made by Levi Strauss & Co. It descends from the copper-riveted "XX" waist overalls patented by Levi Strauss and Reno tailor Jacob Davis on May 20, 1873 (U.S. Patent No. 139,121). The lot number 501 was assigned to the riveted waist overalls around 1890. Over the following decades the model gained a second back pocket, belt loops, a red Tab and concealed back-pocket rivets, and Levi Strauss & Co. marks May 20 as 501 Day.

Text from OyList