Used 1000BASE-LX 1GbE optical transceiver manufactured by Sumitomo Electric. This item was kept in storage without being used. I am listing it because I do not plan to use it in the future. This listing is for one unit. I have two units available, so please inquire if you would like to purchase multiple. - Model: SCFP6F44-GL-CWH - Electrical interface: SFP - Optical interface: LC connector (Single-mode recommended, but it seems to work with multi-mode as well) https://japan.zdnet.com/glossary/exp/1000BASE-LX/?s=4 - Standard: 1000BASE-LX - Brand: SUMITOMO ELECTRIC / Sumitomo Electric Thank you for viewing.