The dome sits on an octagonal base and has an internal diameter of 31.25 meters.

The structures themselves had internal diameters of between three and eight metres.

The internal diameter becomes 10 mm after full expansion.

The internal diameter of the Vienna horn is also smaller than more modern horns.

They have diameters only slightly less than the internal diameter of the pipe to be bent.

The internal diameter is usually 12 to 14 mm (0.4 to 0.5 in.)

Unless the end of the barrel is held steady, it'd take forever to drill out the internal diameter.

It had to able to be passed completely through a two inch (internal diameter) ring.

It is about 15.2m high, with an internal diameter of 7.3m. The walls are 1.8m thick.

Consequently the internal diameter varies, sometimes significantly, from its nominal size.