The Dell Latitude 5500 Laptop Comes in 3 Different Drive Options Depending on the Battery Installed and Supports Single Drive Configuration Only. (One 2.5" Solid State Drive or Hard Drive or One M.2 NGFF (2280) or (2230) Solid State Drive with the Smaller 3-cell 42Whr/51Whr Battery Installed) or (One M.2 NGFF (2280) or (2230) Solid State Drive with the Larger 4-cell 68Whr Battery Installed) Note: Models that have the larger 4-cell 68Whr battery installed do not support 2.5" Drives due to the larger battery occupying the 2.5" Drive bay. When the M.2 (2280) or (2230) Drive is installed with the smaller 3-cell 42Whr/51Whr battery, the M.2 Drive occupies the 2.5" Drive bay. The M.2 (2230) Drive uses a adapter bracket p/n 07HMH to accommodate for the larger M.2 (2280) slot. If replacing the 2.5" Drive for a M.2 Drive, you will need the M.2 Drive thermal plate p/n 85J62 and support bracket p/n KJK50 for installation. If replacing the M.2 Drive for a 2.5" Drive, you will need the 2.5" Drive caddy p/n 5P11T and cable p/n XY5F7 for installation. (The M.2 slot supports SATA and PCIe NVMe Solid State Drives)