Posh CDI No Rev Limiter for 50cc – 150cc 4-Stroke GY6 Chinese Honda Cloned Engines SPECIFICATIONS: Most machines (especially the newer they are) are AC. DC CDI boxes are larger than AC CDI boxes. The easiest way to tell if your machine is AC or DC is to turn on the headlights with the machine turned off and the ignition in the “ON” position. If the headlight comes on, it is a DC machine; if it does not, it is an AC machine. **NOTE: Electrical, High Performance, Aftermarket items are non-returnable, please check photos and specifications before ordering. Please see our Warranty and Returns Policy