SABLUE Bicycle Bike Chain Keeper Holder Dummy Sleeping Hub Tool (01 Black)

It was inexpensive, easy to install, and worked well. We have Trek 7200 hybrid bikes, and I also used it on a Raleigh m20 mountain bike and a Raleigh c40 hybrid bike. It worked for all of them.

It needs teeth to actually spin the chain probably, otherwise, it could damage your RD and Chain.

Cheapest one here, I believe, but easy to use. Really helps with the rear tire work.

This device makes washing your bike much easier. To get your bike clean you have to take the wheels off. This device holds your chain while the rear wheel is removed. It would be better if it was long enough to completely span the entire distance between your chainstays so it wouldn't matter what position your derailleur is in. Instead it clamps just to one side so it will only work if you shift all the way "up" or "down".

I love this because you can take off the back wheel of your bike and clean the drive train with ease. It keeps your frame from being damaged and it is pretty solid. If you work on and maintain your bike as much as I do, GET IT.