I purchased one of these before Christmas. Amazon.com
The stones it comes with wear extremely fast and are pretty low quality with plastic backings. They can however sharpen a knife very sharp.
The real investment in a knife sharpening system is the stones. The stones make all the difference in the world and can be quite expensive.
I have more in stones than I do in the edge pro clone by far.
A few places I purhased stones from.
All 6" Mounted Sharpening Stones, Strops and Blanks - Gritomatic
Edge Pro
Mold Shop Tools - ABRASIVE MOLD & DIE POLISHING STONES
You can purchase a aluminum 1” x 3’ flat at lowes and cut into 6” pieces which will yield you 5 backings to glue the stones to, you lose a little material with each cut.
https://www.lowes.com/pd/Steelworks-3-ft-x-1-in-Aluminum-Solid/3053631
I used 3M 77 spray adhesive from lowes also. Cut your pieces and grind or cut a bevel to match the existing bevel and glue the stones on. You have a lot more choices by making your own.