Shimano ultegra di2 r600 climbing shifter switchright hand remote shift switch to be used in conjunction with di2 levers and can be located on top of the handlebars giving a second shifting position ideally suited for climbing features with di2 technology shifting is easy and precise just a light touch as soft as a mouse click is sufficient for the front or rear derailleur to instantaneously select the correct gear the removal of traditional mechanical cables in favour of electrical wires