Can be used in a variety of occasions such as when traveling, going out, nursing, changing baby diapers. Can be switched with one touch switch. Can be used with 1 AA battery. Specifications: Power Supply: AA battery Size: W 2.6 x D 1.8 x H 5.1 inches (67 x 46 x 130 mm). Weight: 8.8 oz (250 g).