Final answer:
Class II compression stockings are designed to provide a pressure between 30-40 mmHg and are used for various medical conditions under the guidance of a healthcare professional.
Step-by-step explanation:
The class of stocking designed to provide pressure between 30-40 mmHg is known as Class II compression stockings. These stockings are typically used for medical purposes, such as preventing the occurrence of deep vein thrombosis (DVT), managing venous insufficiency, or treating varicose veins. This level of compression is considered firm and should be used under the guidance of a healthcare professional. In the context of blood pressure measurements, the pressure unit used is millimeters of mercury (mm Hg), which also applies to measuring the compression levels in stockings.