What does the double eight slingshot mean?

This means that a slingshot made of beef tendon tires or leather tires has a pulling distance of exactly 80 mm

In slingshot shooting, the pulling distance refers to the maximum distance from the handle of the slingshot to the bowstring. The design characteristics of the double eight slingshot make the distance between the two arms of the shooter 80mm when pulling the slingshot.

This design helps to improve the accuracy and stability of shooting. By limiting the pulling distance, the double-eight slingshot can ensure that the tension of the bowstring remains constant during each shooting, thus reducing the shooting error caused by the tension change.