I saw this sketchbook online (TMall)
- 300g 24pages watercolor sketchbook DWURER brand 12*16cm
- Different series have different % of cotton, need to ask the store

The one i described above is under this link:
【遵爵丢勒水彩本便携式手账本300g水彩纸 水彩本口袋笔记本速写本】http://m.tb.cn/h.3Ta1TuO?sm=154cc3 点击链接，再选择浏览器咑閞；或復·制这段描述￥dAW4bVAHh1x￥后到淘♂寳♀