Shimano Di2 offers the most precise and reliable shifting imaginable, at the push of a button. Adjust the derailleurs once, and the intelligent, auto-trimming system returns derailleurs to the same position every time. The intuitive and user-friendly design can be set up at home and accommodates any frame; new or old.
The Shimano Di2 SM-JC4 junction box connects the electric wires from the rear derailleur, front derailleur, battery, and shift levers. There are two types, external (mounted under the bottom bracket) and internal (for Di2 compatible frames.)
Place an order of $100 or more,
and receive a gift certificate
for 10% of your order total.
Most regular and sale items,
earn you 10% or more back.
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each item page.
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when they have been added to your cart.
Simply enter your gift certificate
at the time of your next order.
Rewards are not transferrable,
or redeemable for cash or gift certificates.
Rewards will be adjusted on,
returns and to reflect any unearned value.