Hey there, The Firefox Road Runner Pro D Plus comes with a Shimano Tourney TY510 coupled with Microshift M22 3-Speed front derailleur. It gets a Shimano Tourney TY500D with Microshift M26L 7-Speed rear derailleur and Shimano Altus EF500 with Microshift TS38 21-Speed shifters whereas, the Firefox Road Runner Pro D on the other hand is equipped with Shimano Acera RD and Shimano Tourney FD. The gears are controlled with EF 500 7 speed shifters. This is one of the major differences between the two models.