Colorful weights assist sensory motor planning. They provide feedback for those with difficulty in vestibular or proprioceptive processing. The O-Rings secure the weights and allow them to be placed anywhere on the writing instrument. Weights are approx. 1.5 oz. each. Weight Kit - 5557-35 includes: 6 weights, 3 grips, 12 o-rings and 12 pencils. Pencil Weight Kit - 5557-36 includes: 3 pencil weights and 6 o-rings.