Step Down models allow 100 volt Japanese appliances and electronic devices to operate in North America. The Japan to North America transformers have two sizes; 150 and 500 watts. 150 watt: 3 x 4 x 2 1/2 inches; 1 1/2 Ibs. 500 watt: 5 x 4 x 4; 5 Ibs.
Step Up models allow 110 volt North American appliances and electronic devices to operate in Japan. The North America to Japan transformers have two sizes; 150 and 500 watts. 150 watt: 3 x 4 x 2 1/2 inches; 1 1/2 Ibs. 500 watt: 5 x 4 x 4; 5 Ibs.