There is a hole at the side in order to open and close it in which you can put the 3mm allen wrench or a T10 torx key which usually belong to the tools of your BMW. With these tools you turn the Oil Filler Plug 120 around (the drilling shows in driving direction).

Hornig emblem and BMW emblem included.

Fits: R1150RT, R1100RT, R1150R, R1100R, R1150RS, R1100RS, R1150GS, R1150ADV, R1100GS, R1100S, R1200C, and R1200CL.

Hornig Oilhead Boxer Oil Filler Cap w/BMW Logo
Produced by Hornig of Germany