I2K Ultimaker 2 Insulator
This insulator will increase the life of your teflon coupler, it will still deform after a while but much slower than without it.
It’s some kind of washer that goes between the teflon coupler and the steel coupler. This makes it possible for the teflon coupler to get less heated. There are still contacts with the hot plastic on retractions this is why it will still deform after a moment.
The steel coupler must be clean inside to install it. Make sure to tighten the steel coupler at maximum capacity to have the maximum pressure on it to avoid filament leasks.
You can read the instructions in this tutorial to install the Olsson block!