That is a very nice setup #fooferdoggie, what is that other thing mounted above?

so here is a small question from me:
My wife and I had 2 allant+7’s and lost them last May in our garage fire, we like those so much we just got new replacements, same bikes but gen2 (love the new controller)
the thing is, that we have still have the old batteries along with charges as they were in the house. They do not fit the new bikes as the plug has been changed.

I would like to get extender myself, so is there an option to adopt those? Or should maybe sell those (eBay or something) and just go for Trek designed one?

cheers