SoundTube AC-JB20-XFMR 70/100 Transformer J-Box20 watt 25 70. 7 100 volt transformer inside a junction box. Includes 4 position tap switch. Can be added to any low impedance speaker. Tap settings include 20 W, 10 W, 5 W, and 2. 5 W (2. 5 W tap not available on 100 V setting). (25 Volt only: 2. 5 W, 1. 3 W, 0. 7 W, 0. 4 W). Specifications Shipping Weight 2. 2 lbs 1 kg Carton Height 3 in 76. 2 mm Carton Length 4. 5 in 114. 3 mm Carton Width 4. 5 in 114. 3 mm