First, I wanted to let everyone know that this works fine in both the 25mm axial coil and 25mm barrel coils. Drops in just fine and works great. Even changes to the same color of gold that the Hornet itself does after burnoff and a little use. Makes sense, IO Hornet says the steel is the same alloy as the Hornet itself (SS316). The adapter matches the length of the Hornet very nicely but the adapter is just slightly longer, so the Hornet itself doesn't contact the bottom of the axial coil.
The Hornet drops into the adapter easily, and I see very little risk of a hot adapter pulling out of the coil and dropping somewhere dangerous! I even tried intentionally fishing the adapter out using the Hornet and couldn't do it. The adapter may lift slightly if you're pulling up at a an angle but it will slip right back where it belongs.
In the 25mm axial coil the adapter bottoms out on the heater coil base and sits up a little in the coil. It also may rock a bit, which could reduce the heat transfer from the axial coil (noted on two samples of 25mm axial coils). Nothing to worry about. Just as IO Hornet says, you'll probably have to increase the PID setting to get similar extraction to what you had from a WOHW v1, for example. I had to go up about 50 degrees, from ~570 to ~620. Always start low and work up unless you are a combustion fan! Minimal hassle once you establish what your setup needs. Just make sure you drop the PID temp when you go back to your 25mm wireless heater!
With the 25mm barrel coil (I have the one from TCC, not the WOHW v2 coil) the adapter drops in fully, with a tiny bit of the adapter showing below the bottom of the coil. I found in the barrel coil that the PID temp should go back down to what you would normally use with your favorite 25mm heater. I suspect that's because there's more coil-adapter contact area than you get with the axial coil.
I waited on submitting this review until I had time to try this adapter with both the axial coil and a barrel coil, as the product title only mentions the axial coil.
Don't see myself needing to buy a 16mm coil (and the hardware to mount it) as this adapter works plenty well in both 25mm axial and 25mm barrel coils.
