- " Doc went back to rummaging around in the space behind the seats [of the DeLorean time machine]. He pulled out a couple of things and handed them to Marty. / 'Here's some binoculars and a walkie-talkie, so we can keep in contact.' "
- —From Back to the Future Part II by Craig Shaw Gardner (quote, pages 139 and 140)
Doc's walkie talkie was one of a pair of Archer Space Patrol walkie talkies that Emmett Brown bought new in 1985A, while Marty was at Biff Tannen's Pleasure Paradise Casino & Hotel interviewing Biff about Grays Sports Almanac, and which they took with them back to 1955 to enable them to keep in touch while Marty retrieved the almanac.
Since the battery in Doc's walkie talkie could not have lasted for seventy years, and was probably removed to avoid leakage, Doc Brown's 1955 counterpart provided fresh batteries for both walkie talkies, duct-taping each one to a large Burgess battery.
Doc and Marty used the two walkie talkies with these oversized batteries to communicate between the train and the DeLorean it was pushing during its final trip.
- ↑ The brand name of the walkie talkies is visible when Marty removes his from the packaging.