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 body comprises an outer surface that defines an inner portion. The proximal end of the body is configured to couple to an ultrasonic transducer configured to produce vibrations at a predetermined frequency and a predetermined amplitude. An extendable folded element includes a first end coupled to the distal end of the body and extending proximally along the longitudinal axis from the distal end of the body toward the proximal end of the body. The extendable folded element comprises a second free acoustic end. The extendable folded element and the outer surface of the body define a single substantially parallel acoustic path.