Oldham Clamp
Ruland Oct16-4-A Coupling, Oldham Clamp, Bore 1/4 In
You will notice the type does not apply, so it's not a specific type.
Ruland Moct25-10-A Coupling, Oldham Clamp, Bore 10 Mm
A nice touch on the ULTRA2 is the non-slip feet that keep it stable on slick floors.