This is 100% genuine Brocade product. It won’t have any compatibility problem with your Brocade devices. And the Brocade 4x16G FC SWL QSFP – 50m Transceiver Module, 57-0000090-01 is factory new with original packaging.
This Cisco 10GBase XENPAK module offer customers 10 Gigabit Ethernet connectivity option for data center, enterprise wiring closet, and service provider transport applications. The Cisco 10GBASE-CX4 Module supports link lengths of up to 15 meters on CX4 cable.