The ghd Duet hair dryer brush is not a rotating brush. Available descriptions indicate that the device combines drying and styling functions, but do not mention a rotating function. In particular, the described technology focuses on a controlled air flow and heated plates, without any mention of a rotating brush.
I can provide the following dimensions:
Length and diameter:
Drum plate dimensions: 37 x 55 mm elliptical shaft with a length of 125 mm. Maximum distance between the opposite bristle tips: 71 mm
The ghd Duet Blowdry is designed with a mains voltage of 230V and can therefore be used in Europe. However, it is not directly compatible with the 110V mains voltage in the USA unless a suitable adapter or voltage adaptor is used.