What is the reported thickness range of a plasma membrane?

1. Plasma membranes range from 5 to 10 nm in thickness. 2. A nanometre is a thousand times smaller than a micrometre, so the micrometre versions of the same numbers are off by a factor of one thousand. 3. A human red blood cell is about 8 micrometres wide, roughly 1,000 times wider than a plasma membrane, which fixes the scale. 4. Because of that comparison, 8 to 10 micrometres describes a whole red blood cell rather than a membrane. _Source: OpenStax Biology (1st ed., CC BY 4.0), Ch 5 "Structure and Function of Plasma Membranes", section 5.1 Components and Structure_