On the picture I see a rather big radiator. But is it suitable for cold water?
GARY P I used the regulator for warm water only. 75 degrees F or above. Cold water diving is a rare event. If you are diving in water that requires attention to the second stage to prevent it from freezing, you should get a second stage specifally designed for cold eater. This is equally true for your safety second stage. If costs is a problem look for used regs. The XS scuba reg is not designed for cold water use.
CATHERINE G I have used it in cold water and have not had any problems.
JEFFREY P I have never used the octo in cold water. My family has used 3 of these on about 80 dives in warm water, approximately 82 degrees with no problems.