Before you order a modchip from us, you need to know which XBOX 360 Controller's PCB Board type you have, so that you can get the correct modchip for your controller.
With the XBOX 360 controller's battery cover removed it will be easy to identify your controller board.
MATRIX PCB : From the battery door area you can see that there is no Capacitor on the left side, while the other two versions do have a capacitor.
CG PCB : From the battery door area you can see that the Capacitor is horizontally oriented.
CG2 PCB : From the battery door area you can see that the capacitor is vertically oriented
XBOX 360 modchips compatibility:
20 Modes: CG - CG2.
23 Modes: CG - CG2.
100 Modes: CG - CG2.
Back Buttons: CG - CG2.