In order to sell you the unit with a serial number, we need to follow Beltronics silly rules that state: "Pro Series are NOT to be sold on eBay, internet or below MSRP. Pro Series are to be sold at MSRP (ie RX65 = $329.99)." Therefore to not break the rules, we need to remove the serial numbers. If you want the serial numbers, we will gladly sell one to you with the serials for $329.99. On this site they are offering it for $197.