Shimano Dura-Ace ST-R9180 Di2 TT Shift/Brake Lever with Wire - Left, 2x, For TT Bars, Black. Single button on each side of the shifting lever only works with Shimano Synchronized Shift. MPN: ISTR9180L - Shimano - Dura-Ace ST-R9180 Shift/Brake Lever - TT/Aero Brake/Shift Lever, Right.
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