4 years & up. Introduce mass comparison with this simple see-saw balance made of 2- piece molded plastic. A visually engaging and tactile way to introduce mass and measurement. Includes 10 weight-related Three Bear Counters and a multilingual activity guide. Balance arm snaps into place, and sliding compensator clips calibrate for easy use. Measures 15 3/4" x 4" x 4 1/4".