A pre-owned BT/GPO 205 rectifier, designed to prevent acoustic shock. The rectifier element conects between the T1 and T2 terminals and should be fitted wherever the rectifier is not present. The 205 rectifier was standard issue on GPO 746 telephones but may be absent on 706, 710 and 711 telephones. The rectifier diode element is not polarity sensitive, so can be fitted either way across the two terminals. Britphone rectifiers are supplied with standard GPO-style fittings to ensure ease of connection. Styles vary, if you have a preference please contact us via email when ordering.