In just 5 minutes, sonic 'shock waves' from this specialist cleaning device will vibrate to dislodge dust, dirt and stuck on grime to keep your glasses, jewellery, shaver heads and more in pristine condition. Add water (and a drop of washing liquid for oil stains) and it is ready to use. Auto switch-off. Size: 7 x 17.5 x 9.5 cm. Sapacity approx 250ml. Requires 3 x AA batteries (not included).