There are two versions, one rack-mounted seat and one frame-mounted seat. This is the rack-mounted version. It includes a winding mechanism that grips the rack; the mechanism can be locked using the included key and unlocked to remove/adjust. The plastic strap is additionally fastened around the seat post for safety.

Please note that your rack must be at least 11cm wide. This is the minimum width so any wider than 11cm is better. (I didn't see this mentioned anywhere when ordering, and -- of course -- my rack is only 10cm so I can't attach the seat without needing to replace the entire rack).

I don't understand the question. Please be more precise.

(Child seat is not to be attached to the frame, but to the luggage carrier)