Dry Heat Slip Cloth cover over the heating pad. Plug into any 120 Volt AC electrical outlet and activate the pad as instructed on the box. Moist Heat Perfect when heat therapy is required to relieve pain; personalize length and time of application with a large LCD display for easy reading. Easy to use push-button controls; select from 10f increments between 120f to 170f; time range 30 - 60 minutes. Feel the heat in 30 seconds. Cloth sponge for moist heat application; penetrates for deep pain relief.