Question about Burley Travoy

The universal clamp is included. It doesn't hold very tightly - probably depending on the seat post: when I take bends with a small radius - for example at the popular obstacles that are often mounted at the beginning of cycle paths - it regularly spoils the clutch for me. But it's not tragic.
If necessary, there are (expensive) clutches on the market that can be screwed onto the seat post. And one that is mounted on the luggage carrier.