This thing is called the Rocketbook Wave Smart Notebook. It works as advertised, fill up the notebook with the included pen then place it in the microwave for a couple minutes to wipe it completely clear!
From the manufacturer –
Introducing the world’s first microwave-to-erase smart notebook. The Rocketbook Wave provides the freedom of a traditional pen and paper notebook, while instantly blasting your notes into the cloud using your smartphone. And when you use Pilot FriXion pens with the Wave notebook, you can erase your notes using your microwave oven and reuse your notebook. Go ahead and re-read that last sentence.
Erase and reuse your Rocketbook Wave up to 5 times using your microwave when you use any FriXion pen by Pilot. Pilot FriXion pen ink turns clear at 140 degrees F / 60 degrees C, and the Rocketbook Wave is specially constructed to be microwave safe. Each Rocketbook includes one black FriXion pen and you can buy more on Amazon and in retail stores.
Take notes in your Rocketbook Wave, download the Rocketbook mobile app and instantly send your handwritten notes to all of your favorite cloud services like Google Drive, Dropbox, Evernote, iCloud, OneNote and more. The joy of pen and paper meets the utility of the cloud.