Semi-automatic E/F mechanism of the right little finger
This mechanism will also add two resonance keys to the lower part of your instrument. An extra key next to your right-hand C/F lever will be used to open the resonance keys. Pressed they will raise the pitch of the E or F. Otherwise everything will play the way you are used to. This mechanism is lighter and allows you to be in charge of when to raise the pitch and when not. The keys can be removed and the tone-holes closed with bumpers if needed. This allows you to play in tune when it is critical but you can play on a lighter instrument when you practice and it doesn't matter. We call it the "democratic" solution.