Mill Finish is the natural appearance of the aluminum as it comes from the rolling mill (Alcoa, Reynolds, Kaiser, or Alcan) or the extrusion mill. It is as is with no external mechanical or chemical finishing. Extruded metal is considered mill finish. All aluminum has an oxide of some varying thickness. Anodizing is a very heavy controlled oxide.
As they are so small of approximately 5-20 micro-metres in diameter, they do not need valves, as there is a distinct flow from the arterioles supplying the capillary with blood, and the venules draining the capillary within the double circulation.
Capillaries are tiny blood vessels connecting the small arteries (arterioles) to the small veins (venules). The blood vessels carry oxygen and nutrients to all the individual cells in the body.apillaries are the blood vessels that lead from the arterioles to the individual cells, and from the cells back to the venules. Capillaries have very thin walls with holes in them, so fluid and small molecules like sugar and waste can move in and out.