Shimano EW-JC304 Di2 SD300 4-Port Junction Box Headlamps Low-profile design with AirScape backpanel

Low-profile design with AirScape backpanel and rolled

descending and traversing

The Accessory Carabiner Set is ideal for keeping keys together

It's a smooth ride no matter where you take it - front side

Shimano EW-JC304 Di2 SD300 4-Port Junction Box Headlamps Low-profile design with AirScape backpanelThe 2nd generation Di2 e Tube wiring system from Shimano has the SD300 designation. These wires and connectors are thinner than the SD50 generation. if you need to join two wires to one (3 total wires), or two pairs of SD300 wires to create a longer length for both pairs (4 total wires), you will need this EW JC304 Di2 SD300 4 Port Junction Box. This is actually a simple looking dual tube connector with internal ports on both ends of each side that