What is the thickness of class II matrix band?: (A) 0.002 inches, (B) 0.002 mm, (C) 0.02 inches, (D) 0.02 mm
Answer is A. 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