The Z-Bands by Zacuto are an option for the Zacuto Z-Finder designed to help secure the Z-Finder in the event it is bumped in a manner that would normally cause it to fall of its mounting frame. The Z-Bands are elastic rubber bands to help hold the Z-finder in place, it is not a way to hold the z-finder on the camera. The Z-Bands are just a security measure to hold the z-finder in place in case of accidental bumping just like the lanyard. The mounting frame and the Z-Bands must be used together. The Z-bands include 4 red aluminum balls and two elastic bands.
PLEASE NOTE: The Z-Bands will not work with the Canon 7D due to the different shape and curvature of the camera. They may work if you have a quick release adapter underneath the camera, which will allow the bands to wrap around and "grip" the camera body.