Shimano Ultegra Di2 Internal Routing Junction Box

A must.

It is an expensive item for its size but essential to install Di2

If you are going to run your Di2 cables inside the frame tues, this is the part you want. The picture is of the external mount box, but the internal box is the one I received. Just remove your crank, plug in your 4 wires, tuck this back into the frame tube, reinstall the protector sleeve and crank and you are all set. A very clean install of shifting perfection!!

I decided to build my new road bike with Di2 electronics. I didn't want to drop $1,500 at one time on the kit so I bought one component at a time. It all came together nicely and all components work fine. I highly recommend this product.

Not much to say about this junction box. It’s a necessary part for installs. This allows you to easily stuff it in the seat tube or down tube to conceal it. I added foam insulation around the ends to make it quieter inside the tubes.

Works great

Wow this thing is so light and tiny! It does it's job, nothing fancy. Good seller...

Once you go Di2, you don't want to go back, although I'm waiting to see if Shimano follows suit with Scram and goes wireless. They also need to focus on mountain bikes as well when releasing new products and not just keep us waiting while supplying the road bike scene.