Forget the Pinnacle Merino-lined products, it's a waste. Yes, it's real merino. However, it's not enough wool to actually provide insulation. Instead, it sops up cold water from the edges and transfers it into the warmer parts of your thermal protection.
The best solution is material. Stay away from extremely stretchy material, like the elastiprene that Pinnacle uses. However comfortable it really is(and it is!) the fact remains it compresses too much at depth. Neoprene insulates by providing a physical barrier between you and the cold water, thus you want as little compression as possible when looking at warmth. Wetsuits/gloves/hoods act as a physical barrier and restrict water flow. A "layer" of water between you and the neoprene is NOT the way they work! They'd work better with NO water!(note the goal of a semi-dry). Thus, find a material that is stiff and doesn't compress. I was all excited about my new Pinnacle Merino gloves and hood only to realize the hard way that it's a gimmik or at least a poorly executed concept. I went back to my old Glideskin Xcel gloves for warmth reasons.
I couldn't disagree with all that was said,
I too was a Merino believer, all my gear when diving wet was Merino. In fact, if they sold a gimmick that would shield my Mask with Merino I would have purchased it.
Let me tell you one thing, MERINO DOES WORK BUT ONLY IN SHALLOW DIVING, with that being said I took my Merino to Ball Buster to do my check out dives for AOW, deep diving.
All suited up in my ME7 wth hooded vest 7mm, I got cold when we reached 103 feet and the drills started.
I even had a 3mm Merino heated torso warmer on that day. To show you how compression works, at the surface I was 13 mm all Merino in the chest.
I never got cold in the chest it was in my head, arms and hands that suffered.
Have you seen how thin the 7mm hoods are with Merino? They are super thin because they say the Merino counteracts for this thinness. They do make 7mm without Merino that is way thicker than the one with it.
This dive was also my first dive of the day, watch out for deep diving in a wetsuit, compression does take it's toll, I wasn't a believer until I took mine down to depth.
Hope this helps you out.
Mike,
ps
It's an incredible suit for up to 60 feet and even shallower than that it's better.