Shimano EW-JC304 Di2 Junction Box - 4 Ports Use With EW-SD300 Labeled Size-700 x 45 Narrow-wide tooth profile keeps the

Narrow-wide tooth profile keeps the chain snug

Graphite ripple powdercoat over steel construction

Two mesh inner pockets keep keys or money safe

Includes a protective carry bag

Shimano EW-JC304 Di2 Junction Box - 4 Ports Use With EW-SD300 Labeled Size-700 x 45 Narrow-wide tooth profile keeps theShimano EW JC304 Di2 Junction Box 4 Ports Use With EW SD300. Shimano Di2 Frame Junction BoxFrame Junction Box connects via SD50 E tube wires to four different points: front derailleur rear derailleur cockpit junction box and battery mount All Di2 components on the bicycle require the same firmware version. Using Di2 components with different firmware versions may cause malfunctions Use Di2 system checker to update component firmware from http: e