The dermis has connective tissue, blood vessels, oil and sweat glands, nerves, hair follicles, and other structures. It is made up of a thin upper layer called the papillary dermis, and a thick lower layer called the reticular dermis. Epidermis. The outer layer of the two main layers of the skin.
A fastener is a hardware device that mechanically joins or affixes two or more objects together. Fasteners can also be used to close a container such as a bag, a box, or an envelope; or they may involve keeping together the sides of an opening of flexible material, attaching a lid to a container, etc. There are also special-purpose closing devices, e.g. a bread clip.
Length. Fastener length is usually measured from where the surface of the material is presumed to be when the fastener is installed, to the end of the fastener. US fasteners are measured in inches, while metric fasteners are measured in millimeters (mm).