通販でも店舗でも普通に売ってる。

http://kakaku.com/item/K0000988628/?cid=shop_google_00010004%26aacmp%3Dshop%3Alisting%3Agoogle%3AG0001&;ef_id=WdkR5AAAAHntOByY%3A20171007220042%3As
https://www.amazon.co.jp/s/?ie=UTF8&;keywords=gpd+pocket&tag=googhydr-22&index=aps&jp-ad-ap=0&hvadid=191994393276&hvpos=1t3&hvnetw=s&hvrand=17074885107040016664&hvpone=&hvptwo=&hvqmt=e&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=1009331&hvtargid=kwd-282552724480&ref=pd_sl_3i4qtqx5sf_e
http://pc.watch.impress.co.jp/docs/news/1082737.html