Biller Pilot Trainer 170-E Lufthansa w/Box, Manual, & Batteries

I recently found this item at a local gargae sale and am looking for some more information on it. It has the original box, owners manual, "D" batteries, and appears to be in very good condition. I tested it with a new set of batteries, and everything seems to work. All four of the propellers work as you move the left and right throttle handles up, the runway belt begins to spin once a certain speed is reached, and as you pull back on the yoke, the plane rises off the runway and the landing gear retracts. The box top is not in the best of condition and the owners manual is yellowed. I have searched the internet and can not seem to find to much information on this item. Thanks for any help you can provide, and have a great day!