I finally got one of the last remaining parallels I was chasing from 2017 Heritage.
I've previously shown shortly after release the following
Gold Chrome /5
Flip Stock, Bright Yellow, Color Swap, Blue Border, and assorted chromes
Throwback SP yesterday
The issue I had when cataloging this particular card, was the spelling of it.
I always spell it grey, but Topps labels it as a Gray back. Cardboard Connection has it listed as a Gray Back also.
In doing some quick research, both Gray and Grey are acceptable ways to spell the neutral color.
Despite the confusion with the spelling, I am extremely happy to cross this off the list. I only need 2 chrome versions (Superfractor 1/1 and Purple Hot Box refractor).