This adapter is for use in the U.S. with 0-50 watt 220-240V products. It"s safe for battery chargers, portable electronic devices, cell phones, MP3 players, electric shavers, etc. and allows 220-240V appliances to work on 110-120V U.S. electricity. It"s designed for long-term use/charge with appliances rated 0-35 watts and its thermal fuse provides temperature protection.