You just wind it up and wear it on your finger, no need for batteries. It's always ready for action.
When you touch anyone with the point they get will be shocked by the vibration and the noise the buzzer makes! This is a great joke to play on your friends and family, ask them to shake your hand and then Zaap, the look on their face says it all! See if they can hold onto your hand during the shock. They will laugh with you when they know it is a shock buzzer.
It's only 1 inch long and light enough to carry in your pocket, handbag etc.
They make great gifts and come with instructions.