A sling was an ancient weapon used to throw a projectile or missile made of clay, lead, or stone. To hold the projectile, it had a small cradle attached in the middle of two cords. One needed to place the middle finger or thumb through a loop on one end of the cord, while a tab at the end of the other cord was placed between the thumb and forefinger. The sling was swung, and the tab had to be released at the right moment, freeing the projectile.
Rope Slings
Rope slings Palm fiber Roman Period Karanis, Egypt University of Michigan Excavations. KM 8354, 8358