Teksavers is a worldwide reseller of Cisco equipment. We help businesses, consultants and government clients buy or sell Cisco products like the QDD-400G-DR4-S. Related Search Terms: New used refurbished buy sell purchase preowned The Cisco 400GBASE Quad Small Form-Factor Pluggable Double Density (QSFP-DD) portfolio offers customers a wide variety of super high-density transceiver modules and the flexibility of 400 Gigabit Ethernet connectivity options for data center, high- performance computing networks, enterprise core and distribution layers, and service provider applications. The QSFP-DD modules are our new generation of 400G transceiver modules based on a QSFP-DD form factor.