Thanks for bringing your concern to us. @joshuad11, thanks for your kind reminder
Indeed, after our test, it shows both the PowerCore + 26800 PD and the PowerCore + 26800 QC are incompatible with the HP Spectre series. Really sorry for the bad news.
Should there be further issues or questions, please feel free to contact us via "firstname.lastname@example.org", we would try our best to assist at any point.
Best wishes to all of you~~