These clamps are readily available in the UK and Europe but not here that I can tell. Peter Parfit did a video review of these clamps a while back. Does anyone here know where I can get these clamps in the US?
Well Bessey.co.uk has them but does not ship to US.
Axminster apparently doesn’t have them, at least yet.
The Bessey.co.uk website says “ships in September”, so maybe they just haven’t crossed the Atlantic yet.
FYI - dug up pictures and those look just like the Mafell rail clamps that you can get from Timberwolf.
They aren't cheap - I think $80 for a set of two.
They do work really well in the Mafell rails which has a slightly smaller channel.