As correctly pointed out by ASimpson, there are classification of fits which are application specific. He lists the metric version, imperial are equivalents noting 1.0 inch = 25.4 mm. There are several good references on this, look to the web. But the Machinist Handbook does discuss this, at least in the 23rd edition.
How does Dhea work? DHEA is a parent hormone produced by the adrenal glands near the kidneys and in the liver. In men, DHEA is also secreted by the testes. It is changed in the body to a hormone called androstenedione. Androstenedione is then changed into the major male and female hormones.
DHEA is a precursor to female sex hormones estrogen, progesterone and testosterone. It is often called the âmother hormoneâ because it is the source that fuels the bodyâs metabolic pathway. Like most hormones, women have optimal DHEA levels in their 20s. After that, DHEA levels slowly decline with aging. There is an 80% decline in DHEA by the age of 70. Age-related decline of DHEA is inevitable, but the decline in DHEA associated with chronic stress and adrenal fatigue is not. Women who are chronically stressed exhaust their adrenal glands, which results in low cortisol and low DHEA levels. Prevention and/or treatment of adrenal fatigue will prevent this.