SHIMANO ACERA RD-M3020 8 Rear Derailleur 7/8Speed for MTB Mountain Bicycle Original Shimano Bike Parts PRODUCT SPECIFICATIONS MODEL NO RD-M3020-8 SERIES ACERA M3020 Series Color Black Rear speeds 8/7 Compatible chain HG 8/7/6-speed Top-Normal spring type|Double servo ✔ Mount|Direct attachment (Conventional) ✔ Cable adjuster ✔ Max. front difference 20T Fluoric coated link bushings 1 Pulley|Teeth 11T Pulley|Sunken type pulley bolt ✔