What's the difference between titanium slingshots of six and eight?

6mm is too small. Slingshot specifications are 8mm, 9mm, 10 mm. 9mm is the shape of most people's hands. 8mm is suitable for people with small hands. 6mm is the same as the bow I used to hold with wire when I was a child, but it is too thin. Baidu search: Longcheng outdoor defense, all kinds of slingshots.