There is a switching unit on the road bike's handlebar, which combines the functions of the switching and braking levers, in short it is called the shifter. Aside from SRAM and Shimano, Campagnolo also comes into play as manufacturer of shifters. Other than the flat handlebar, which is used on MTBs or trekking bikes, the road bike shifter has two functions. Firstly, the shifter controls the switching of the gears. In order to go onto the next larger sprocket, the lever (respectively a part of the lever) is klicked / swivelled inwards. Depending on the manufacturer, there is a smaller lever or thumb switch (that is what Campagnolo calls it) beside the lever, which then effects the gear change onto the smaller sprocket. Secondly, the shifter also controls the brake cable. Even its position is different, as the shifter is mounted vertically onto the road bike's handlebar (on its outer bend), there, they are fixed by means of a clamp, the screw is hidden behind the rubber cover. Pay special attention to the compatibility of the shifter to the rear derailleur in order for the gears to run smoothly.