Great quality for the price. You won't be able to find something equivalent in Japan for less than 5000 jpy.
I bought it combined with the air silicon mat and the result was very satisfying, for the first time I was able to have a crusty base in my Galette des Roies (french kind of pie).
Only caveat of the product, it does not fit into the rails of Hitachi oven which is 410mm wide so I am not able to slide the plate in the middle of at the top of the oven.