AC or DC
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.
Chinese 6 pin dual plug DC CDI fits many 4-stroke models of ATVs, dirt bikes, go karts, scooters, and mopeds.  Many size engines require this CDI, including 50cc to 250cc.  Verify the number of pins and style of plug for best match of your CDI.  Also do the test at the top of the CDI page to verify that you need a DC CDI.

CDI description:
6-pin [4 spade male + 2 spade male] please note the position of the spade terminals
Rounded dual plug [as pictured]
80mm long [3.16"]
48.6mm wide [1.91"]
DC
Known to fit, Buyang, Coolster, Dinli, Redcat, SunL and Tao Tao, along with many other manufacturers. 

Package including :
1pc of the 6-Pin DC CDI Box