High-quality auto transformer series provides the advantages of excellent frequency response, low insertion loss and reliable performance for volume control application in 25V and 70.7V systems. Attenuation is accomplished in ten make before break steps plus positive off position. (No stop between maximum and off position to prevent switch damage). Contacts are silver plated for noise-free operation. Features a removable terminal block. Includes stainless steel plate, with stamped and filled or screen printed dial scale and a skirted black knob (White and ivory plastic plates with matching skirted knobs also available in Decora style-see AT model description chart).