They’re 15mm thick – the thinnest I found anywhere and likely the minimum thickness that’s strong enough to work properly – but alas, they won’t work with Champion wheels because their mounting surface doesn’t have the necessary recesses for the lug bolts that attach the adapter to the hub. Comes complete with all hardware.
One pair is new and unused in a sealed box; the other pair was test-fit to the car but never driven on. Best price I found on the 'net is $175/pr, so let’s say $250 plus shipping via PayPal OBO.