Assist sensory motor planning and provide feedbacts and allow them to be placed anywhere on the writing instrument - See more at: http://funandfunction.com/pen-pencil-weights-p-351.html#sthash.8abK6jwh.dpufk for those with difficulty in vestibular or proprioceptive processing * O-rings secure the weights and allow them to be placed anywhere on the writing instrument * 3 weights included * Weights are approximately 1.5 ounces * Age 3+