Ultrasound therapy has been widely used for about 80 years. It belongs to the national basic treatment program, which used to be applied to pain department and rehabilitation and physiotherapy department,now it comes to family used. Ultrasound is applied to the body using the ultrasound probe, an ultrasound gel is used to transmit the ultrasound wave into the surrounding body parts. The ultrasound wave can penetrate to a maximum depth of 7cm and deep heat is produced. The continuous sound waves travel deep into the tissue and induce vasodilation,which helps increase blood flow to the treated area and is found to help relieve pain and reduce muscle spasms. It comes uniquely equipped with a soundhead pre-warming feature on an ergonomically designed sound head for increased patient comfort.Before starting therapy the soundhead preheats so that it's more comfortable and warm.Once therapy is engaged,the pre-warming feature turns off to allow for the most effective treatment. With three output intensities,and three treatment time selections,the aluminum sound head is watertight for use in underwater therapy (for 30 minutes),though only the metal portion is watertight - you can not submerge the entire sound head.This new and improved portable therapeutic ultrasound unit is a great choice for non-invasive pain relief.No more pain meds or pills,this unit is very similar to the one used in your Chiropractor's or Physical Therapist's office.Very effective in pain relieve Application: Relieve Pain Reduce inflammation fast perfect for reducing scar tissue Sports injuries - Neck & shoulder pains, ankle injuries, groin injuries hamstring strains... Sciatica pain, arthritis pains, joint pain, muscle pain Soft tissues injuries recovery Cellulite reduction Item Name: Ultrasound Physiotherapy Device Rated Voltage:100-240V, 50/60Hz, 600mA Frequency: 1MHz Timer:3 Levels (5min/10min/15min) Effective Radiation Area:4cm Effective Ultrasound Wave:3.0W/cm Pulse repetition rate:100Hz10% Duty cycle:Low 30% - Medium 40% - High 50% Plug Type:US Plug, it applies to Canada, India, Mexico, Thailand, Taiwan, the United States, the Philippines and so on. Colour:White Material:Plastic Package Contents: 1 * joint massager Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.