The US-91A is one of the four older style Golmar speech amplifiers still available.
Golmar US-91A Speech Amplifier
The Golmar US-91A is one of the four older style Golmar speech amplifiers still available.
The connections on the unit are as shown in the close up image.
Features:- two pots for adjusting the speech volume at both the panel and handset
Dimensions:155mm x 85mm x 30mm