Although there are no instructions, searching the internet for "golf practice balance board usage" will bring up several videos of similar products that you can refer to. ・Size: Approximately 73cm long, approximately 29cm wide (measured by an amateur + from the internet) ・This is a device for practicing weight transfer and center of gravity movement during a swing. ・A "click" sound device is attached to the back, which indicates the timing of weight transfer with a sound. Although it is unused, it has been opened once for content confirmation and photography. It will be repacked in the original box and shipped with a shipping label attached. Thank you for your understanding.