Any NVMe drive of the same size (M.2 2230 or 2280) and possibly M.2 2280 in place of the M.2 2230 -- for that detail, you'll need to provide the full model number (Precision 3550, etc.).

Thanks a lot.

The model is: Precision 3650 Tower CTO Base

There are multiple options depending on how your system is configured and whether you want to replace or add a drive.  See here

https://www.dell.com/support/manuals/en-th/precision-3650-workstation/prec_3650t_ss/storage?guid=guid-c4a3bd50-15d5-421c-b2f6-d609f9d94d15&lang=en-us

Thanks so much for the quick responses.