Bolt Block First wooden screwdriver and bolts - ages 2-5 Young children can turn the six big, chunky wooden bolts with fingers alone or they can use the jumbo wooden driver. Any bolt turns smoothly in any threaded hole. Once they have mastered turning, children will notice they can match bolts to holes by color. Driver stores securely in its own (unthreaded) hole. All wood. 6" x 1¾" with 6 bolts and driver.