Electric Black Leg And Thigh Massager operate on electricity. They use rollers and balls to massage the foot. Electric foot massagers use vibration and kneading technique to massage the soft tissues for relaxing the stress. They use a motor which vibrates the rollers using oscillation technique these massagers also have additional features like heat to provide relief more than a manual one. Some of them also include water to mimic the spa benefits of relaxing the feet. As they are powered by electricity, electric ones are suitable for everyone like people who have pacemaker. If you have any medical issues related to heart.