Only if you have an S100 model. There are differences in the hardware and b-knuckle, so you may use the Half Mount on S100 derailleurs, but it cannot be added to other derailleurs. If your S100 derailleur didn’t include this, you can purchase part number 11.7518.120.000 for an upgrade. Please note, the UDH Half Mount still requires the use of chain gap and limit screws for proper set up, unlike UDH Full Mount derailleurs. Additionally, your frame must be UDH compatible in order to use the UDH Half Mount.