Spanish

RS-001

RS-001

At the back, left, British Post Office relay model C, non polarized, differentially wound, manufactured by B.I. & H. Co. Ltd. Liverpool.

At the back, right, British Post Office relay model B, polarized, differentially wound, maker unknown.

At the front, left, British Post Office relay model A, polarized, differentially wound, maker unknown.

At the front, right, polarized, differentially wound relay, manufactured by Walters Co. London.