The Dell Precision-3530 Mobile Workstation Comes in 2 Different Drive Options Depending on the Battery Installed and Supports Single and Dual Drive Configurations. (One 2.5" Solid State Drive or Hard Drive with the Smaller 4-cell 68Whr Battery Installed and/or One M.2 NGFF (2230) Solid State Drive in the WWAN Slot) or (One M.2 NGFF (2280) Solid State Drive in Primary M.2 Slot with the Larger 6-cell 92Whr Battery Installed and/or One M.2 NGFF (2230) Solid State Drive in the WWAN Slot) Note: Models that have the larger 92Whr battery installed do not support 2.5" Drives due to the larger battery occupying the 2.5" Drive bay. When the M.2 (2280) Drive is installed in the primary M.2 slot with the smaller 68Whr battery installed, the M.2 Drive occupies part of the 2.5" Drive bay. If replacing the 2.5" Drive for a M.2 Drive, you will need the M.2 Drive thermal support bracket p/n X3DN4 and mounting bracket p/n 2FFR0 for installation. If replacing the M.2 Drive for a 2.5" Drive, you will need the 2.5" Drive caddy p/n 6F7DD and cable p/n 6NVFT for installation. The M.2 2230 to 2242 adapter board is required to install a M.2 (2230) Drive in the WWAN slot. (The primary M.2 slot supports SATA and PCIe NVMe 3.0 x4 Solid State Drives and the secondary M.2 WWAN slot supports PCIe NVMe 3.0x2 Solid State Drives)