The D5 Pump Plate seals off any Singularity Computers D5 Pump Top without installing a pump, so that the coolant flows through the pump top. This is specifically for items such as the Spectre Dual Loop Side Panel, to block off the pump top if only the one D5 Pump on the Spectre main Distribution Plate is required.
Purchase D5 Pump Plate
https://singularitycomputers.com/product/d5-pump-plate/