This is an old Schrader Tire gauge. It was supplied for the United States Tire Co. branch agencies or dealers everyw The instructions direct the user to apply 20 pounds of air per inch of width. 21/2 inches-50 pounds 31/2 inches-70 pounds 4 inches-80 pounds 41/2 inchess-90 pound 5 inches-100 pounds 51/2 inches-110 pounds and 6 inches-120 pounds. The origional leather case is in good condition. Please email any questions.