We have been looking for a professional grade ultrasonic that can match the performance of our Ottosonic line of ultrasonics, and we think we have found one in the Best Built line of ultrasonics from Korea. The Best Built ultrasonics are the most powerful ultrasonics we have ever tested, out-performing our Ottosonics in a side by side demonstration using the aluminum foil test, a simple test that gives you demonstrative results of an ultrasonics power. The Best Built ultrasonics totally destroyed (that is a good thing)! the aluminum foil, with noticeably more holes than our old Ottosonic, and considerably more holes than the less powerful (and less expensive) GemOro ultrasonics.