These wooden pulleys are great for Kids STEM and craft projects at home, at school and at camp. Decorate with paints, stains, embellishments and more. The inside hole is approximately 3/16" diameter. Set includes two 3/4", two 1 3/16" and one 1 1 7/8" diameter 7/16" thick wooden pulleys. These are craft items, not intended to be used with Toys and Joys plans.