If you currently using Di2 or considering making the purchase, you need to think about this remote shifter unit. This satellite switch, also known as a climbing shifter might just be the coolest Dura-Ace Di2 accessory you can own and use. In short, it is a small unit that zip ties securely to the top of your right handlebar to give you another shifting position. Imagine, if you would, climbing on the tops and being able to make those, oh so important, one gear shifts to feather your effort - without having to move your hands down to the brake-shift levers. During an effort, it makes your job a whole lot easier. Install them, get used to them and you will likely upgrade them from frill status to necessity.
As with the rest of the Di2 components, the construction is durable and the engineering is reliable. They will function day in and day out without issue. Set up is a breeze and they are a pleasure to use. The perfect complement and 'necessity' to a Di2 group. Package includes one remote shifter with zip ties for the rear derailleur and needs a pair of Di2 brake shifters to function - it will not work alone or as a primary shifting unit.