CISCO 40GBASE-CR4 PASSIVE COPPER CABLE

Cisco 40GBASE-CR4 Passive Copper Cable - Direct attach cable - QSFP+ to QSFP+ - 3.3 ft - twinaxial - tan - for Catalyst 3016; Nexus 3016, 3064-E, 3064PQ, 3064-X

You use QSFP+ transceivers with networking ports used for uplinking and downlinking. For low-cost connections to switches in the same or adjacent racks, use QSFP+ transceivers with copper cables.