The Acer Predator Helios 300 PH317-55 Gaming Notebook Supports up to 3 Drives. (One 2.5" Solid State Drive or Hard Drive and/or Two M.2 NGFF (2280) Solid State Drives) Note: Both M.2 slots support PCIe NVMe Gen4.0 x4 Solid State Drives and can be set up as RAID Drives. If the 2.5" Drive was not installed from Acer, you will need the 2.5" Drive bracket p/n 33.Q7LN2.001 and cable p/n 50.QC2N2.001 for installation.