[QUOTE=Bishop;9655516]Holly tank inserts batman, looks like a great way to get an extra min runtime...

But seriously, it's like the size of my thumb tip, I pulled the tank out of the bag and though it looked kind of large, opened the cap and there is the big black insert.

The MTX4s came with an insert similar to what you've described, but it needs to be removed to get 75ml of fuel into the tank. I've been told that the max. allowed fuel tank volume is less in somewhere, and that's why they have a removable insert.

Kindest regards,
Lars.