The U.S. made personal portable transceiver BC-611 got a very good reputation in World War II, it was the earliest really portable "walkie talkie".
Like in a huge telephone handset the microphone and speaker are integrated in the cabinet of the set. The set is switched on by unscrewing the cover of the antenna and by pulling out the telescopic antenna. To talk, just push the "push-to-talk" button. There are no other controls or knobs to operate the set.
The transmission / reception frequency is controlled by a single crystal in the 3,5 - 6 MHz shortwave range, the frequency is written on a small tag on the cabinet and cannot be changed in case of co-channel interference. Later, the frequency channels have been coded by different label colours, to You just had to use two sets with the same frequency label colour.
The standard range is only 150 - 200 m under standard conditions, unter optimal conditions, the set might reach up to 1,5 km - malicious gossip has it that a powerful megaphone might be at least as useful...

The set is powered by a 1,5 V heaters batterie and a 103,5 V B+ / anode batterie, batteries will keep 10 up to 20 hours depending from the intensity of transmitter use.