Realizing the promise of liquid paper­—lightweight digital surfaces that can be written on, erased and saved as easily as traditional paper—is an elusive goal, but a new tablet from Kent Displays is getting close.

The Blackboard, released in October, weighs about 10 oz and is made of plastic. It uses power only when a button at the top is pushed to erase, and its replaceable button-cell battery should last five years, or 50,000 cycles, says the company’s CEO, Albert Green. Kent has been making liquid-crystal displays since 2010. Green says, “We believe this is the best writing experience to date.”

The surface consists of two sheets of plastic that encase a layer of cholesteric liquid crystals. Pressure from the pen point causes the crystals under it to reorient themselves to reflect light. An eraser on the pen can reverse the process selectively, and images can be locked. A smartphone camera app with minor editing functions, such as cropping and contrast control, captures images as JPGs or PDFs and syncs and saves the images with your calendar. “If you are taking notes at a certain time, it will save those notes in the Outlook calendar,” says Green.

The surface is shaded, but translucent for use like tracing paper; patterned templates can be fit in the back as writing or drawing guides. The device sells for $45.