HP ZCentral 4R Dual PCIe Slot RiserHP ZCentral 4R Dual PCIe Slot Riser PCIe 5. 0 x16 Dual Slot Expansion The HP ZCentral 4R Dual PCIe Slot Riser is a purpose built expansion solution designed to unlock flexible, high bandwidth PCIe connectivity within HP ZCentral 4R workstation enclosures. This dual slot riser card enables you to add or upgrade essential expansion capabilities while preserving the tight, streamlined cable management and robust airflow you rely on in remote workstation