To activate this mohawk bracelet simply pull the battery inhibitor locayed on the side of the bracelet near the on and off button. These bracelets come in three different colors; Pink, Blue, and Clear. Dimensions: 4 inch circumference. 2 inch width. Fiber optics are multi-colored and 2.5 inches long. The modes are: steady, slow chaning, flashing, strobing, and blinking. Included 3 replacable AG13 Batteries.