I was at the beach wearing my sling and decided to take some photos at a surf and lifesaving club. The reflection in the window has distorted the photo but you can spot the two back strings running from my shoulder blades to butt.
This is the white wrap I've worn on other occasions from my house to the beach. It is 7.5 inches high at the front and when worn like this about 6 inches on the back. When walking on the streets I normally wear it with a shirt which half covers it.
The front are also double strings.