QSFP-DD (Quad Small Form-factor Pluggable Double Density) modules use a different connector than traditional QSFP modules. The QSFP-DD connector is designed to accommodate the increased number of electrical lanes and support higher data rates. It has a double-density design, allowing for more contact pins.

The QSFP-DD connector has a total of 8 electrical lanes, compared to the 4 lanes in a standard QSFP connector. Each electrical lane can support data rates of up to 25 gigabits per second (Gbps), providing a potential total data rate of 200 Gbps for a QSFP-DD module.

The physical appearance of the QSFP-DD connector is larger than that of a standard QSFP connector due to the increased number of lanes and contacts. It retains a similar form factor, making it backward compatible with QSFP modules. QSFP-DD modules are used for high-speed data transmission, and the double-density design allows for increased bandwidth in networking applications, such as 200 Gigabit Ethernet and 400 Gigabit Ethernet.