It's a simple bit of kit, but it sure does work.
In car front loading CD player was constantly skipping or refusing discs, one use and it now works perfectly.
I also have an old Traxdata CDRW recorder that had got into the habit of allowing me to record, but refusing to finalize the disc so it will play other machines. Again, just one use and it now successfully finalizes every time.
I'm sure it wont fix every problem, but from my experience I can't fault this product.