A venerable design, that still functions, much more reliably than some newer inventions we might add. So whether you're timing an egg, a naughty child, or your stand mixer, you can rely on this. The sand doesn't lie, and it doesn't require any batteries either. Additional Details ------------------------------ Product description: A venerable design, that still functions, much more reliably than some newer inventions we might add. So whether you're timing an egg, a naughty child, or your stand mixer, you can rely on this. The sand doesn't lie, and it doesn't require any batteries either.