Thank you for viewing. I bought these hoping my child would learn the correct form and run faster, but the Dash Driver Zeku was only used once indoors to make sounds. The Dash Beat was only taken out of the box and is unused, still in its bag. I have confirmed the operation of the items for this listing. ◆MIZUNO Dash Driver Zeku ~Excerpt from the official HP~ To run fast, in addition to leg strength and foot rotation, forward propulsion through correct arm swinging is necessary. Swinging your arms forward and backward widely, with your elbows at a 90-degree angle, is the ideal arm swing that Mizuno proposes. "Dash Driver Zeku" was jointly developed with the toy manufacturer Takara Tomy Arts Co., Ltd., and is an item that allows children to learn the arm swing form for running while having fun, and to master the correct way of running. It looks like a hero's item, and by simply wearing it like a wristwatch and running, it notifies you of the quality of your running with sound, and it also includes a function that changes the sound when your arm swing becomes faster. ◆MIZUNO Kids Dash Beat ~Excerpt from the official HP~ You can learn the technique of "bringing your feet forward compactly" which is necessary to run fast. Please purchase if you understand that these items have been stored at home. If you have any questions, please comment. ꙳★*゜Please read the profile before purchasing.꙳★*゜