yellow box - where to get - worth it


I am going to a 42T rear gear and hear the yellow box is what I want, where to get it, any problems etc.??
Depends how accurate you want to be. I was dead on to my GPS with 19/41. I am only slightly off with 18/40. When I need to be accurate I just use my GPS, seemed like a lot to go through with the Yellow box. Nice once you get them set I guess.
I was reading that the 3rd gen yellowbox is plug n play w/factory link plugs on end, no more soldering. If so might be worth it. Dont know about you but Im running out a room under my seat.

The Yellow Box is made by Black Robotics it's a pretty small unit (2" x 1"). It corrects your speedometer and odometer errors. I'm not that concerned about the speedo error, but I would like to correct the odometer error.  No reason to register more miles on your bike than you have to.

There is a new Yellow Box v3 that has a 3-wire output and plugs in between your speed sensor and the speedo. The online instructions are not currently available. You can correct your gage error from -28% to +28%.  The cost is about $100, pretty steep for a little box, but I have not heard any complaints about the product.

I currently have a 42 rear sprocket, when I change the front to a 16 I will order the Yellow Box.
I am at 16-42 and was off 19% with a GPS. Stock gearing I was off 7%. Easy to install and easy to use. I think it is well worth $100 just to keep extra miles off the bike which will increase the value of your bike in the long run!