battery not included Easy to use, smart and power savingOne-key operation of DS The operation is simple, and both grandma and 5-year-old child can use it easily. Silver knob and black body, just turn the knob to set the time, press to start or stop. The digital light will dim after 5 seconds and turn off after 5 seconds to prolong battery life. [Magnetic & Time Management] With magnets on the back, you can stick to classroom whiteboards, cookware, tasks, student tablets, iron walls, refrigerators, gyms, or other steel places. Time management that helps students focus on study, showers, games, etc., classroom teacher organization, mothers cooking, baking, eggs, also helps people with autism and ADHD ease transitions and encourages independence and productivity for all abilities. [Large LED Display and Constant Brightness Function] 3-inch large screen with constant brightness function. Numbers are easy to read from a distance. Even in large conference rooms, classrooms or large kitchens, gyms. [Loud alarm and digital flashing function] 3-level alarm sound mode, can be silent, normal or up to 90db. There will be no unnecessary beeps when making timer settings. The alarm can be heard in another room without worrying about overcooking. In silent mode, flashing LED numbers will remind you of arrival time.