I am sorry that the G40 string lights are not low-voltage. Both its output and input voltage is 110V~120V. We considerately upgrade the G40 bulbs replaceable. The 100 Ft (50 bulbs) model comes with 3 spare bulbs, and the 50 Ft (25 bulbs) comes with 2 spare bulbs. If any of the bulbs are defective, easily replace the defective bulbs with the spare bulbs instead of replacing the whole string.