I picked up a 510 extension for my Ego-t batt and it keeps the switch cool to the touch. It seems like the Dart is functioning much better with the extension also.
I really feel a 510 extension should be standard kit with TV products. Both the revolution and the evolution.
I love the high quality metals (brass base means it holds lots of heat) but they also transfer heat a bit too well. When I use my revolution on my Apex Ultra I notice the top of the ultra heats up faster than the revolution body itself. I also find the Ultra turns into a red hot blob of magma when you try to use the evolution on it. It works, but only if you can endure the painful burn that comes with your hit.
In comes the 510 extension. I would prefer an adapter made specifically for temperature insulation, but failing that a large 510 extension makes a world of difference. Not only does it keep your hands below the pain threshhold, it helps the device perform better.
Since the revolution or evolution doesn't waste energy heating up the body, more of the energy goes directly into heating the part that is supposed to be hot. This means it will heat up faster and extend your battery life.
I really wish TV would come out with their own insulating adapter...