Here are some details that I pulled from radiomuseum. Org. Power type and voltage. Dry Batteries / D: 4 x 1.5 Volt. Permanent Magnet Dynamic (PDyn) Loudspeaker (moving coil). Plastics (no bakelite or catalin). Eight Transistor AR-851 [Without CD marks]. Packard Bell Co. Tablemodel, with any shape – general. As used in Gilligan’s Island Television program. This model, without CD marks. Was produced later than the similar model with them. There are no current models that verify the AR851 model number, and this appears to be based on references from the Gilligan’s Island TV show. Very similar to Aiwa AR851.