Why not purchase it directly from here? The "Compatibility Information" shows the Inspiron 14 7420 2-in-1. Again, ignore the restriction concerning Precision FHD+ panels.
I just bought the Inspiron 14 7420 2-in-1 that on Dell's page says it's a 14", FHD+ 1920x1200, 60Hz, Touch, WVA, TrueLife, Narrow Border, Pen Support.  When looking for accessories, Dell promoted as one of the accessories to be the Dell Active Pen PN350M so I purchased it. The pen doesn't appear to support this laptop and I looked at the PN5122W and PN7522W and both say they don't support FHD+. My frustration is the breakdown of information so I hope someone with better insight then my poor experience with tech support could be better. Speaking to tech, they claimed that the PN350M won't work with my laptop yet sale's manager says yes it does. Can anyone with better knowledge confirm or point me in the right direction to a Dell Active Pen that can actually work with this model? Thank you and sorry for the long post. 
Inspiron 14 7420 2-in-1, Active Pen support?