This pack of 2 replacement locks will keep the lower cover (that secures the filter) in place on your extractor fan. Its a genuine part that will fit select models of Bosch, Neff and Siemens cookerhoods. Please check Models This Fits to make sure this lock is right for your cookerhood. Please note: Bosch advise that you will require an adjustable clamp/grip (eg. plumbers grips) in order to fit this part. Apply slow pressure until the parts click together.