Abstract: Disclosed herein are methods and devices for restricting the blood flow of an area in a subject. The device includes a restrictor, a bolt and a strip. The restrictor includes a cylindrical body having one open end, one closed end, and a passage there through, in which the inner surface of the cylindrical body towards the open end is treaded; and a protrusion disposed on the outer surface of the closed end of the body. The strip is preferably made of an elastic material and is coupled to the protrusion of the restrictor at one end, while allowing the other end (i.e., the free end) to circumvent the area before passing through the passage of the cylindrical body to form a loop that can be tightened to restrict the blood flow of the area in the subject.