The MA 27 dependability has made it a favorite of school nurses for years. Rugged, all-in-one housing and large, fingertip control knob provides access to a full range of frequencies. Switch between tone, pulse or warble by simply pressing a button. Equipped with a rigid yet lightweight case with built-in handle and storage compartment. Ample storage holds headphones and other accessories. Air conduction from 250 Hz to 8 kHz. Easy fingertip operation of frequency and hearing level controls.