The nadir hole is a cone shape when shooting with the tilt up. So when there are large knobs, screws, plates, etc. on your tripod, the Tripod Extension can be used to make the objects appear smaller, and can possibly hide them in the nadir hole.
For example, with the panohead for the Sigma 8mm f3.5 lens used with Google Business View, the Google blur box in the nadir is about 62mm diameter at the bottom of the panohead. The typical Manfrotto tripod column is 59mm diameter. If your tripod column is larger, the Tripod Extension can be used to raise the lens by another 100mm, and increase the Google blur box to 100mm diameter at the bottom of the extension.
When shooting for Google Business View, we recommend not to use a ball head. Simply attach the panohead directly to the tripod column, and use the tripod legs to level the panohead. It is also possible to hide the tripod legs inside the Google blur box.
Only the Tripod Extension and 1 thread adapter to 1/4" UNC are included. (other objects in the photos are not included; panoheads, cameras, lenses, and software are not included)