Thank you for viewing. Operation has been confirmed. The stone has been changed to a stone that produces fine bubbles. It will not deteriorate and become crumbly. (The stone will be shipped as new.) Hapyson YH-708B Product Specifications Batteries used: Size D x 2 Battery life: Strong: Approximately 55 hours continuous Weak: Approximately 150 hours Airflow rate: Strong: Approximately 1.0L/min Weak: Approximately 0.45L/min Size: Approximately 80 x 40 x 150mm Weight: Approximately 480g (including batteries) *Excluding stone Motor life: Approximately 1,000 hours