What is the thickness of class II matrix band?
There are two types of bands:

Uncontoured bands
Precontoured bands

Uncontoured bands
These are available in two thicknesses:

0.002 inch (0.05 mm)
0.0015 inch (0.038 mm)

Sturdevants operative dentistry south asian edition page 204
0.002 inches
0.002 mm
0.02 inches
0.02 mm