... for part number: Part NumberDescriptionASFP1G-40-S31-C1000BASE-EX 40km SM 1310nm SFP, without DDM, 0 ~ +70 °CASFP1G- ... 40-S31-X-CD1000BASE-EX 40km SM 1310nm SFP, with DDM, 0 ~ +70 °CASFP1G-40- ... S31-I1000BASE-EX 40km SM 1310nm SFP, without DDM, -45~+85°CASFP1G-40-S31- ... ID1000BASE-EX 40km SM 1310nm SFP, with DDM, -45~+85°C Product ...