Check the listing for details. The Digi Sync Pro Throttle Body And Carb Sync Tool 2 Channels. Condition: New. Listed at 204.55 USD. These units are 100% functional. Units have a factory defect such as a smudge or scratch on the lens. The defects typically can't be noticed once the unit is turned on because the brightness of the LCD screen hides the defect. Most blemishes are so small that you won't find them unless they're pointed out. The Digi Sync - DS3+ - With Version 3.2 Software 2-Channel: Works on vehicles with 2 Carbs or Throttle Bodies Each unit comes with the following: -Padded storage case -Internal magnet -Replacement vacuum caps -Set of 5mm & 6mm adapters -Short tube - Useful for installing the adapters Balancing will improve the response, smoothness, mileage, performance, and operating temperature of your engine. Digital synchronization is better because it is more accurate and does not pose the risk of sucking manometer fluids into your engine.