In February 2015, Planar Systems unveiled a 55" Full-HD transparent OLED prototype, and now the company launched this display as a commercial product branded as the Planar LookThru display.
Planar is now accepting pre-orders for these displays, with mass production beginning in February 2016. The standard model pricing starts at $14,995.
This is the largest transparent OLED ever produced. It's highly likely that the actual display producer is Samsung Display, who recently launched their own 55" transparent and mirror OLED displays.