Add A Bit More: When you just need a litttttttttle more length between your AMP output ballast and the input to your bulb or AMP/D2S adapter. These are a life saver! These extensions will add a whopping 28 or 40 inches of length between your ballasts and bulbs. Universal: Protected in the middle with a hard, yet flexible, rubber lining they have standard male/female "AMP" inputs and outputs on both ends that are compatible with 99% of HID Ballasts and re-based HID bulbs. NOTE: Sometimes old/used ballasts have trouble striking HID bulbs when their high voltage is passed through an extension like this, so new ballasts are recommended.