the 6 speed massager is portable, lightweight and rechargeable it has 4 massaging heads for different type of work 1) round head -for thighs, waist, arm , legs and calves .. 2) U- shaped head -for neck, spine, achile tendon massage 3) flat head - for large muscle groups( arms and thighs) 4) bullet head - for impacting deep tissue massage( joints and palm etc The massager can activate the muscles, stimulate blood flow, greatly reduce muscle recovery time, relieve pain and relax from head to toe. specifications Charging Voltage: 110-220V Charging time: 2-3 Hours Working time:5-6 Hours Battery capacity: 2000mAh 6 level speed: 2100 rpm to 3600 rpm Operating Mode: Pressing the button