They are usually in plastic. "Packstyle 紙 WB 24 10"
<a href="//commons.wikimedia.org/wiki/User:Syced" title="User:Syced">Syced</a> <a href="//commons.wikimedia.org/wiki/File:%E6%9D%B1%E4%BA%AC%E3%81%AE_%E3%83%A9%E3%82%A4%E3%83%95_%E3%82%B9%E3%83%BC%E3%83%91%E3%83%BC%E3%83%9E%E3%83%BC%E3%82%B1%E3%83%83%E3%83%88_%E3%81%AE%E7%B4%99%E3%81%A7%E3%81%A7%E3%81%8D%E3%81%A6%E3%82%8B%E7%94%9F%E9%AD%9A%E3%81%AE%E3%83%88%E3%83%AC%E3%82%A4_2.jpg#P170" title="Edit this at Structured Data on Commons"><img alt="Edit this at Structured Data on Commons" src="https://upload.wikimedia.org/wikipedia/commons/thumb/8/8a/OOjs_UI_icon_edit-ltr-progressive.svg/10px-OOjs_UI_icon_edit-ltr-progressive.svg.png" decoding="async" width="10" height="10" style="vertical-align: text-top" srcset="https://upload.wikimedia.org/wikipedia/commons/thumb/8/8a/OOjs_UI_icon_edit-ltr-progressive.svg/15px-OOjs_UI_icon_edit-ltr-progressive.svg.png 1.5x, https://upload.wikimedia.org/wikipedia/commons/thumb/8/8a/OOjs_UI_icon_edit-ltr-progressive.svg/20px-OOjs_UI_icon_edit-ltr-progressive.svg.png 2x" data-file-width="20" data-file-height="20"></a>
<span class="int-own-work" lang="en">Own work</span> <a href="//commons.wikimedia.org/wiki/File:%E6%9D%B1%E4%BA%AC%E3%81%AE_%E3%83%A9%E3%82%A4%E3%83%95_%E3%82%B9%E3%83%BC%E3%83%91%E3%83%BC%E3%83%9E%E3%83%BC%E3%82%B1%E3%83%83%E3%83%88_%E3%81%AE%E7%B4%99%E3%81%A7%E3%81%A7%E3%81%8D%E3%81%A6%E3%82%8B%E7%94%9F%E9%AD%9A%E3%81%AE%E3%83%88%E3%83%AC%E3%82%A4_2.jpg#P7482" title="Edit this at Structured Data on Commons"><img alt="Edit this at Structured Data on Commons" src="https://upload.wikimedia.org/wikipedia/commons/thumb/8/8a/OOjs_UI_icon_edit-ltr-progressive.svg/10px-OOjs_UI_icon_edit-ltr-progressive.svg.png" decoding="async" width="10" height="10" style="vertical-align: text-top" srcset="https://upload.wikimedia.org/wikipedia/commons/thumb/8/8a/OOjs_UI_icon_edit-ltr-progressive.svg/15px-OOjs_UI_icon_edit-ltr-progressive.svg.png 1.5x, https://upload.wikimedia.org/wikipedia/commons/thumb/8/8a/OOjs_UI_icon_edit-ltr-progressive.svg/20px-OOjs_UI_icon_edit-ltr-progressive.svg.png 2x" data-file-width="20" data-file-height="20"></a>