Industrial Ethernet Copper to Fiber Converter (or vice versa) - ST connector.  Ref: SE-MC2U-ST Industrial Ethernet Copper to Fiber Converter (or vice versa) - ST connector.
STRIDE SlimLine Industrial Unmanaged Ethernet Media Converter, Lexan housing, -10 to +60 deg. C operating temperature range, one 10/100BaseT auto-detecting, auto-crossover and auto-polarity RJ45 Ethernet port and one multimode 100BaseFX ST fiber port. Redundant power inputs with surge and spike protection, DIN rail mounting. Supports Store and Forward wire speed switching and full-duplex with flow control. UL/CUL1604 (Class I, Div. 2, Groups A, B, C, D) and CE marked.