Good Octo for Cold Water ?

[rsingler]

Well, the Mk2 first stage is not "rated" for cold water. But since it will be used for a single 8-minute controlled ascent, I don't think icing is what should control the choice for the pony. Probably true for the second stage as well but I'll defer to the Michigan divers on that one.

Pony aside, I don't disagree with your comments.

 

[halocline]

My preference is the ScubaPro MK-II, teamed with a "vintage" 109/156. The MK-II first is about as rugged as it gets, and inexpensive to maintain. The all brass 109/156 handles the cold superbly, and again, will take just about any abuse you can dish out. Again, maintenance is inexpensive. Perfect as a pony reg.

This combo was on my pony a week ago in 41 degree water of Tobermory.

Assuming the OP is looking for a complete regulator for his pony, I would agree 100% with this suggestion.