Love this machine. I have been using handheld ultrasonics for years. They are amazing on pulled muscles, bruises, and sore ligaments. This one has a pulse feature that really helps. This is the model that works the best. The pulsing can be felt if you hold this on the skin between the thumb and forefinger. There are many models, but this is the strongest one out there. Shipping was faster than stated by a month, and the item was well packed. Highly recommend. I am buying two more.