The new Dell Precision 3550 and 3551 share a design, but not the internals - one of them is based on Comet Lake U CPUs, the other uses Comet Lake H series processors from Intel. Both models are optionally available with a pointing stick, which makes them unique among this years Dell Precision workstations: Dell has stopped offering this feature on the more expensive Precision 7000 series.
https://www.notebookcheck.net/New-Dell-Precision-3550-3551-Last-Precision-laptops-standing-with-a-pointing-stick.465720.0.html