Caution Avoid prolonged use of this product. Take a break at about 30 minute intervals. Stop using this unit immediately if you begin to feel tired or if you experience discomfort or pain in your hands, wrists or arms during use. If the condition persists, discontinue use and consult a doctor. This product is intended for use with the hands only. The vibration function of this product may aggravate injuries. Do not use the vibration function if you have any ailment or injury to the bones, joints