The Yacker Tracker is a traffic light that will monitor the decibel level in your classroom. This self-standing or wall-mounted unit signals by using the green light when sound levels are low, yellow when there is too much noise, and red when the sound level reaches 15 decibels above the adjustable sound level meter. The red light can be programmed with optional alarm sounds. Features include a voice that says "Quiet please"A in 4 languages, siren sounds, a delayed alarm function that will sound when noise continues for more than 2 seconds, longer lasting LED lights, and optional face stickers. AC adapter included, but can also be powered by 6 AA alkaline batteries-not included. The remote control unit has a 20 feet range and requires 2 AAA batteries, which are included. Intended for adult use in K-12 grades.