The Fitbit Zip Wireless Activity Tracker FB301C is a unisex device that comes in one size and requires batteries. It can be used both indoors and outdoors and is compatible with various operating systems. The device measures heart rate, speed, time, distance, and calories burned. It features a 0.96-inch display, accelerometer, GPS, and wireless connectivity. It is designed for gym and training, weight lifting, yoga, and running and jogging. The device is lightweight, made of plastic, and weighs 6oz.