Instead we had bought these lockable bracket (handlebar adapter) and mounted, because otherwise you would always have to take the bag even if no valuables inside are.
The plastic is very high, the steel cord is coated so that the handlebar is not scratched. Overall, stable and practical.
Please look handlebars of your bike if this at least in the middle is thicker with 31.8mm diameter, then the urgent oversize clamps additionally purchase (normally clamps to 26mm case).
