The HP ZHAN 66 Pro G1 Notebook PC Supports Single and Dual Drive Configurations. (One 2.5" Solid State Drive or Hard Drive and/or One M.2 NGFF (2280) Solid State Drive) Note: If the 2.5" Drive was not installed from HP, you will need the 2.5" Drive hardware kit p/n L01083-001 (Includes: hard drive service door, hard drive cover and cable) for installation. (The M.2 slot supports SATA and PCIe NVMe Solid State Drives)