QSFP-DD DR4, 4x100G Optical transceiver module are designed for use in 400 Gigabit links over 500m singlemode fiber.
400G QSFP-DD
The 400G QSFP-DD Transceiver follows the same port densities system as the QSFP and QSFP28, but the QSFP-DD will support eight lanes instead of four lanes for the QSFP and QSFP28, which double the density.