Abstract: An end effector for use with an ultrasonic surgical instrument. A body extends along a longitudinal axis. The body includes a proximal end and a distal end. The proximal end of the body is configured to couple to an ultrasonic transducer configured to produce vibrations at a predetermined frequency. A folded element includes a first end coupled to the distal end of the body at a predetermined region between a node and an antinode. The folded element extends along the longitudinal axis from the distal end to the proximal end of the body. The folded element comprises a second free acoustic end. A distal portion of the body and the folded element define a parallel acoustic path.