Cisco - GBIC transceiver module - GigE - 1000Base-LX - SC - up to 6.2 miles - 1310 nm - refurbished - for P/N: 15454-FC-MR-4/ 15454-FC-MR-4=/ 15454-G1K-4/ 15454-G1K-4=/ 15454-G1K-4-RF