Description
The sling was a small rectangular or oval piece of leather or woven material with cords attached to the two ends. The leather or cloth was slightly smaller than a man’s hand, and the cords were about the length of an arm.
Usage

Translation
If possible, translators should avoid using a word that will be understood as a modern slingshot or catapult made with pieces of rubber. In 2CH 26:14; JOB 41:28; and ZEC 9:15, the focus is actually on the stones and not on the weapon. In these passages the translator may avoid mentioning the sling; for example in JOB 41:28 b GNT has “rocks thrown at him are like bits of straw.”
The Greek word sfendonētēs in JDT 6:12 and 1MA 9:11 describes not the weapon but the person who uses it, the “slinger.” In JDT 6:12GNT says “who used a sling as a weapon.”
Where such a weapon is unknown, it may be possible to say “a special weapon for throwing stones.”