STERLING TELEPHONE AND ELECTRIC Co. Ltd
BATTERY AND VIBRATOR CALL
PORTABLE TELEPHONE (British Army Type)
No. U 539
For Military Purposes, including Morse Signalling.
The whole mounted in stove enamelled Brass Case, and carried in solid Leather Containing Case, fitted with Shoulder Strap.
Taken from the Sterling Catalogue No. 11 & 12
Last revised: April 28, 2021