CTD's price for a 10 or 20 pack is quite reasonable ($2.65 each for 10, $2.49 each for 20). The single pad price is high; I'd guess CTD probably just doesn't want to fill single pad orders. Many other online vendors have a similar pricing structure for single vs, multiple pads.
Yes, as pointed out, they are not a new invention. They are a rebranding of a Joest (Jost) product. Abralon and Siaair originally licensed their products from Joest.
The construction seems to be a cutting fiber mesh over a thin sponge base. There seems to be a distinct space for the material to collect below the cutting fibers. I believe this to be the main advantage. Also, I prefer this 5-inch size because it fits my hand block better (minimal creasing.)
I find them to cut quite nicely. For hand finishing (dry) they are especially nice.
To clean after using dry, just slap on a table edge a few times, rotating the pad. You can, of course, clean these wet as well.
I recently purchased a 10-pack and just started using them, so I cannot speak to their longevity. First impressions: I'd say I will order these again, instead of Abralon pads.
I have no affiliation with CTD.