If you need to know which HD2 camera you have, you can use the following information:
The easiest way to determine which camera version you have is to check the top of the camera unit. RLACS329 has an orange strip along the top with RACELOGIC written in black. RLACS222 has a dark blue strip with RACELOGIC written in white.
You can read more about the cameras and their specifications here.