J4858C-PCW is a 1000BASE-SX SFP Transceiver, generic for HP J4858C. It is guaranteed compatible for all HP switch and router product lines. This transceiver can be mixed and deployed with HP OEM transceivers for seamless network performance and interoperability. PC Wholesale offers a LIFETIME advance replacement warranty on all transceivers (compared to 90 days from most OEM manufacturers).