Using an air-tight pouch within the shell, the Imperial harness molds to your back when you pump the air out of it, creating a truly customized fit. $269 Visit Bay Area Kitesurf for information about this product in North America. 

The Underwave Imperial Vacuum Harness is the first harness of its kind that we’ve seen. It features Underwave’s Vacust technology. Instead of typical foam padding, the middle of the harness molds to your body when you use the included pump to pump the air out.

The Imperial Vacuum Harness also features a quick release buckle, hold down strap, and integrated hook knife. The vacuum pump attaches to the right side of the harness with a quick release connection that seals the Vacust patch when you disconnect the pump.

As you pump air out of the harness, it becomes more firm and molds itself to conform to whatever is against it. You can place your hand on the harness, pump the air out, and it will hold the shape of your hand.

OK, so that’s a neat trick, but what does that mean on the water? When molded to your back, the Imperial Vacuum harness feels different from other harnesses. The best way to describe it is that it feels like it provides more lumbar support to the small of your back.

You can definitely tell that it fits the contours of your body and this seems to help the harness stay exactly in place. It had no tendency to ride up or slide from side to side when riding.

The compact profile gives the rider a lot of freedom of movement and the Vacust patch seems to give you a little extra support right where you need it.


  • Unique Vacust technology creates a truly customized fit.
  • Compact profile offers a lot of freedom of movement.
  • No tendency to ride up while riding.


  • The compact profile means it is very non-restricting but also means that the load is not spread out over a large area of your back.
  • It’s easy to pump too much air out of the harness, creating a hard spot in the middle of your back.


  • You only need to pump a small amount of air out of the harness to create the custom fit (only two-three pumps). If you pump more air out of the harness, you can actually make it too hard to be comfortable while riding.
  • You don’t have to mold the harness every time you ride. The patch will retain its shape from one session to the next.

The Verdict:

The Underwave Imperial Vacuum Harness is a very unique product that mold to the contours of your body. The compact profile makes it a very good harness for riders who want to maximize their range of motion on the water. It fits comfortably into the small of your back and stays put while riding. The Vacust patch seems to provide more support than the standard Underwave Imperial harness without giving up any range of motion.