Cable plug tool for Di2

Cable plug tool for Di2

Non-series components TL-EW300

Shimano's TL-EW300 Cable Plug Tool is one of those tools that you only use when building or maintaining your bike. It allows you to securely and properly connect and disconnect EW-SD300 electric wires, connecting your Di2 components to each other.

While you could actually plug in and unplug the older EW-SD50 Electric Wire by hand, doing so with the newer EW-SD300 wires is not recommended. The wires are simply too small to grab properly. You're far more likely to twist and break these wires doing it by hand.