Spyder Arctic Series tube diameter?

What is the diameter of the tube on the Blue Spyder Arctic from WicedLasers... the part that goes around the battery tube where you hold it...?
Overall specs say ~36mm but I think that is the overall diameter of the aperture and cap.
The tube portion I'm looking at appears to be arounf 25mm-30mm. Any info on this anywhere?

Thanks for any help!

If your talking about the battery compartment, look up what battery it holds and then find out the diameter of that specific battery.