This goes on the inlet side of the filament buffer. Simply slide your PTFE through it, push the PTFE through the buffer, and then pop the button in place. When you wish to release the PTFE just push the button into the buffer to release the PTFE, then pull the button back out a little when you are ready to reinsert PTFE. This stays in place all the time, and will hold its place in the buffer when you have the tubing removed. No more tools to release the PTFE!