You can install this oil level control (also called oil level glass) if your original oil level control is broken or yellowed. Exchange it when you do your next oil change. Sometimes it is easier to break the glass of the old oil level control in order to remove it.
Outer diameter: 40mm
259E R 850 GS 95- (0403)
259E R 1100 GS 94- (0404,0409)
R21 R 1150 GS 00- (0415,0495)
R21A R 1150 GS Adventure 01- (0441,0492)