Visual timer operates easily with just 2 dials: a green total alarm time dial, to choose the desired duration from 5 to 120 minutes, in 5 minute increments, and a yellow warning dial, to set a time for the warning alert. Counts down until the coloured light glows and the alarm sounds. Supports visual-only timing when you adjust volume or turn off the sound completely. Plastic. Requires 3 AAA batteries (not included). 8.25 x 8.25 x 12 cm high.