Sony TC-50

The TC-50 was a compact pocket cassette recorder (tapecorder) manufactured by the Sony Corporation. It was intended for dictation purposes and became famous due to its use by NASA in the Apolo missions. This small battery powered voice recorder was carried by the astronauts in the command module during lunar missions to record crew log. This is a mono (2-track monaural) unit with built-in 2-inch loudspeaker, and microphone. It has the SONY-O-MATIC feature, which automatically controls the recording level. The circuitry requires three penlight (UM-3) batteries, which provides up to 4-½-hours of continuous recording time. The battery compartment can also accept the BP-10 rechargeable battery pack, which provides 2-½-hours of continuous recording time.

Value/eBay

The TC-50 sometimes comes up for sale on eBay, and the price is usually high due to its fame and popularity. A unit in mint condition together with the packaging and accessories is highly desirable and can fetch a tidy sum on a good day. However, if you can get the actual one used by NASA astronauts (as shown above), then that would be priceless today. If you cannot afford to get the TC-50, then there is also the more improved version TC-55, which has much in similarity with the TC-50, but is relatively affordable.