ROLLERS AND OTHER MODIFICATIONS FOR THE FINGER KEYS
The standard instrument includes four rollers for the little fingers.  These are for the right hand low F/G sharp and for the left hand low E flat/C sharp keys. 

For additional information download “Finger Key Rollers and Modifications for Fox Contrabassoons.”

Rollers for Left Hand Third Finger C/E Flat Keys

Roller for Little Finger F Sharp Key

Touch Extension Tab for Right Hand 1^st Finger