UPC-A and UPC-E leftmost digit is the "number system digit"
Leftmost digit...
0,1,6,7,8,9 are used on most products.
2 (and 02) are for Weigh Scale Bar Codes
3 Drugs
4 Local Use -wild west, make them up and use them in your own controlled environment. Often used for loyalty cards, and with some systems (not Acme) used for store coupons. Typically small manufacturers that want to make up their own codes use 4 as the leftmost digit, and they inform their customers that their codes are for local (not universal) use.
5 Used on Legacy UPC-A Coupon Bar Code Formats
Need to create your own item numbers? See Label Printing
