need help on identify seed pixels

[frankpeter2006]

Hi all — three years ago I bought Pebble Seed Pixels. I have both 5 V and 12 V . While troubleshooting with a Raspberry Pi, I messed the pixel strings . How can I identify which are 12 V and which are 5 V? both wire size are same.
Thank you for your help.

 

[merryoncherry]

If it doesn't light on 5V try 12V We may be able to tell from looking at the exterior, but often times not.