I assume you mean for M.2 storage. The 7506 has one M.2 slot which is for an NVMe/PCIe SSD. This description is from the support page for the 7506. Your Inspiron 7506 2-in-1 Black supports one of the following storage configurations:● M.2 2230/2280 PCIe/NVMe solid-state drive● M.2 2280 PCIe/NVMe solid-state drive + 32 GB Intel Optane Storage● M.2 2280 PCIe/NVMe Intel Optane Storage
If it has two slots, are both NVMe? 
Inspiron 7506 2-in-1, storage slots?