This exercise is from an IronMind / Brad Johnson publication.
Baseball / Softball from Sports Authority – this will depend on hand size and exercise selection
3/8 x 6” Eye Bolt w/Nut (for Baseball)
3/8 x 8” Eye Bolt w/Nut (for Softball)
7/16 Spring Link (holds 320 pounds each)
Drill with 3/8 Bit
Drill the 3/8 hole thru the center of the ball. Feed the Eye Bolt thru and secure the nut.
Push the Eye Bolt thru until it emerges on the other side and enough to grab some threads until the nut if engaged flush to the bolt.
When they are done they should look like this
The Spring Link secures to the Eye Hook and allows you to piggy back these on Gymnastic Rings if you already have them. If you do not have Gymnastic Rings, you can use a rope or chain and the Spring link still allows for a quick release.