The Craziest Knife Sharpener - Here's The BENEFIT of the Tumbler Rolling Sharpener 

1 - They don't even post a link to their product. lol. 2 - This is 98$ not including shipping. A normal whetstone is 20 - 30$. 3 - Whetstones produce much better results. That knife should be effortlessly gliding through the paper quickly. If you want to blow 100$ on something you can do much better. Buy a whetstone, cheap knives and practice.

Then they wear out and you buy another one a whet stone will last years longer and you can fine tune the edge with them.

中国地区能买吗？

Takes all the fun and skill out of a true art form. No thanks.

Trendy bullshit