The Finisar FCLF-8521-3 10/100/1000 BASE-T transceiver is a Duplex SFP transceiver for optical communications, rated for distances up to 100m and a maximum bandwidth of 1.25Gbps. 1000BASE-T RoHS 0 to 85C Copper SFP Transceiver. Finisar FCLF-8520-3/FCLF -8521-3 1000BASE-T Copper Small Form Pluggable (SFP) transceivers are based on the SFP Multi Source Agreement (MSA). They are compatible with the Gigabit Ethernet and 1000BASE-T standards as specified in IEEE Std 802.3. Note: Due to manufacturer restrictions, Finisar FCLF-8521-3 is a non-cancellable & nonreturnable product. Please call to confirm stock. This product is manufactured by Finisar USA, ships directly from Finisar and is covered by full manufacturer warranty within the USA.