It's a head button. It serves no purpose other than something to put your thumb on so as to slow down the rotor after landing, which is only something you might want to do on big helis where the rotors spin for ages. On small helis it's purely cosmetic.
You can take it off, if you don`t like the looks of it. It won`t affect the performance of the helicopter at all.
I keep mine on for doing button scrapes..LOLNo worries, the first crash and that thing will remove itself lmao. Most just take them off.
I keep mine on for doing button scrapes..LOL