Secondary Cooling Unit

The Secondary Cooling Unit does its job to cool the vapor. It's a bit easier to put in place than to take apart.
When the secondary cooling is well install into the airflow tube, there is a tiny rattle if you shake the stem (a captive cap is way louder than that).
For a locked MouthPiece + SCoolingUnit set up, you need two O-rings on the airflow tube (get a O-ring from the spare that comes with the Revolve stem).

Sitting at the mouth piece, it doesn't get dirty fast, like others style of twisted bits, which are usually place near a Dyna tip.
With the Direct airflow tube, you can feel the cooling slowly decreasing at the end of session, nothing annoying.

I'm not a fan of the secondary cooling unit with the DRC air-path, it's too much cooling, I don't need it and the flavor start to suffer.
However, I'm a big fan of the secondary cooling unit with the Direct air-path. I feel a similar flavor/vapor temp experience as a SC Vort.x with a high flow interc..ler.

Now the big question, for the Direct airflow users: Can you also put an SCU in the condenser of the Revolve Cooling Unit, near the Dyna tip end?
Yes, the CU condenser is wide enough to fit one there.
And no, it's 1mm too long. You can't use a reclaim filter screen anymore, and there is a 1mm gap between the tip to sleeve side, or the Cooling Unit to sleeve side.
If you can live with this gap issue (you will now see two grey O-rings on a 5 fins Ti tip), why not.

Compatibility of the SCU with other stem?
Not really. It can fit a Simre..C condenser, but the fit is very loose for this wide condenser.
DynaV condenser are wide enough, but the larger part can't go inside the tip, so no choice to cut the condenser to size.

Compatibility V1-V2 parts:
-V2 Cooling unit only accept V2 MP with V2 airflow tube
-V1 Cooling unit can accept V2 MP with V2 airflow tube
-the version of MP and airflow tube has to be paired together, V1+V1 V2+V2
-secondary cooling unit need a V2 airflow tube, so a V2 MP too
-V2 reclaim screen filter can clip and stay in place only into the V2 Cooling unit
-sleeve fit both versions

for Revolve V1 owners:

You have to buy the V2 MouthPiece if you want to use any V2 airflow tube and V2 secondary cooling unit.
I recommend it for your Revolve V1 if:

you want to keep your V1 and buy a Revolve V2.

you can't afford a V2, you always set your DRC to MTL and you like a tight draw, get a V2 MP and the V2 DRC airflow tube.

you can't afford a V2, you want the maximum cooling possible with the combo V2 MP, DRC tube and secondary cooling unit.
IMO it works, yes, but it's not for me, the flavor is too much muted.

you want to keep your V1, you like the Direct airflow tube and want to try the V2 secondary cooling unit upgrade. That's what I have done for my V1.
V2 MP + V2 DirectTube + V2 SCU with a wood sleeve (but I also have a Revolve V2 for DRC use).

you can't stand anymore the O-ring often sliding with the MP and miserably falling, when you pull the V1 MouthPiece in spinning mode.

Other than these use cases, I don't think it's worth to upgrade your V1, you are cover with the V1 as it is, or , simply grab the V2 to get all the features.

Love it saved me paying out on gen2 I just added this to my Gen1 and works a dream.
Fantastic company to deal with also