I want to give a review of the K-edge chain catcher I have been using about a month.
This thing works!

I started riding a new corse for my daily ride in the spring. It has extreme topo change requiring lots of front shifting. I was dropping the chain at least once every ride. Not fun approaching what looks like a wall & finding yourself freewheeling.

A bear to set up because you must remove the front D to bolt it on, but once on it does the job!