I found a local store to buy 18mm birch plywood (made in Russia), the store is about 28KMs away from my home. So this weekend I made a BB slingshot for my boy, here it is. The width of fork is about 5.7cm, from fork top to handle bottom is 12.5cm With "easy" thera-band and homemade leather pouch. Ammo is normal plastic BB ball. I mean "easy" because I cut the thera-band much longer with narrow width, so my boy can enjoy shot it in home without break any thing. I'm sure he will love it. HaHa.