Not a Velcro strap.
It's a secure strap, it's mounted over the laptop and fastened (clicked) on the table. Actually it's rock solid when it's secured, and it makes sure all laptops fit, MacBook air is also no problem, a MacBook with spec case also works.
The "fun" thing about tethertools is that they keep coming up with new additions to the line up, I fell in love with the jerkstoppers and think that's a must have when shooting tethered. I also use the table and some accessories and like that a lot, but the digi one with the holes (kickstarter project) also looks nice, although I don't really like the fact that my laptop would be clamped down on the table on the corners, I'm always afraid something will "break" when using that kind of connection, plus when the MacBook pro goes more towards the MacBook air you have a problem.