Lock Arm awnings are considered the most popular External Blinds. These awnings are known to provide protection against the sun by keeping the ultraviolet rays out but allowing light in through a window in any living space.

These awnings are manufactured with a maximum width of 3950mm and fitted on the outdoor side of a wall, covering an opening, usually placed 150mm over each side of the window reveal, to secure the awning to a brick (not in between mortar) or to a wooden substrate. They are also recommended for installation between two columns or posts—say a gazebo or front porch. If installed under an eave, a hood is rarely fitted since the overhang will provide protection to the awning.