This is a genuine Cisco GLC-SX-MM 1000BASE-SX SFP Transceiver Module that is brand new and has never been used. It is compatible with various Cisco networking devices and is designed to provide reliable and high-speed connectivity for your network. With this module, you can easily expand your network and enjoy fast data transfer rates of up to 1 Gbps. Whether you are looking to upgrade your existing network or setting up a new one, this Cisco GLC-SX-MM SFP Transceiver Module is an excellent choice. Buy with confidence knowing that you are getting a brand new, high-quality product that meets Cisco\'s strict standards.