Fortinet FN-TRAN-SX FTLF8519P3BNLFTN 1 Gigabit Mini-GBIC Switch Module 850nm 1Gb. Worked fine when removed from corporate environment, upgraded to 10Gbps modules, so no longer needed.

Can be collected if preferred or if you want to meet for collection that can be arranged as well. Item in Slough (just outside M25 West London, near Heathrow Airport)

Any questions feel free to ask, I take payment through eBay or cash on collection if preferred.