This part is a kind of semiconductor called 12-MMF-003-5-A.

Function of this product has Power Line Filters.

Manufacturers : api

Image and pinout :

Some of the text within the PDF file :

Power Line Filters Dual Stage 12-MMF & 12-MMB Series Features I Suitable for products that must conform to FCC regulations I Excellent attenuation for high voltage impulse I Metal case provides effective EMI shielding I Two stages for excellent filtering characteristics I Structure provides effective shielding for noise generated both externally and internally I Operating temperature: -40°C to +85°C I High performance I Low leakage current Applications I Digital equipment I Switching power supplies I Personal computers and peripherals I Measuring instruments and medical equipment I Telecommunications equipment I Equipment requiring very high noise attenuation Circuit Diagram Circuit 1 Circuit 2 Circuit 3 Specifications Model Rated Voltage (@ 50/60Hz) Rated Current Leakage Current ( [ ... ]

12-MMF-003-5-A PDF Datasheet Download