With this Shimano 105 R7000 Derailleur Upgrade Kit you can purchase everything in one go if you want to place a lighter or heavier gear on your bike. This is very handy when you go to the mountains for example. In addition, this combi-offer has an excellent price-quality ratio! To be used with all 11-Speed Shimano Shifters This combi can be used on all 11-speed Shimano shifters. So it doesn't matter if you have 105, Ultegra or Dura-Ace shifters. As long as the shifters are 11-speed. Shimano 105 R7000 Rear derailleur The Shimano 105 R7000 rear derailleur has an excellent price-performance ratio. The rear derailleur is designed with Shimano's Shadow-Link design, making it better protected and faster shifting. Thanks to this design you also have better shifting performance in poor conditions. Shimano 105 R7000 Cassette Just like the derailleur, the Shimano 105 R7000 Cassette has a high price/quality ratio. Even with a lot of pressure on the pedals, this cassette still shifts smoothly because of the shifting lines on the teeth. You can recognise these lines by the teeth that are sometimes half ground or have notches. The gears are also coated to make them more durable. Different ratios There are multiple cassette ratios to choose from for different terrains. For example, the cassettes ending at 25T more are used on the flat and slightly sloping roads. You use the 28T for hilly roads and the 30T, 32T and 34T for the real mountain rides. All this of course taking into account whether you drive compact, semi-compact or double. Shimano 105 HG-601 Chain The Shimano 105 HG-601 Chain is an excellent 11-speed chain. The chain is sharpened with precision, which makes your shifting fast and smooth. Also, the links are reinforced, making this chain also suitable for racing bikes with electric drivetrains. Derailleur cable? It is likely you also need another derailleur cable to get the derailleur working. You can find these cables here .