Mind the Gap!
As with most of the reviews, I needed something to fill the dreaded gap between my mattress and headboard. 
My reason is a bit different, though the gap has always annoyed me. My Minature American Shepherd likes to unmake the bed. She goes to the head of the mattress and pulls the top sheetblanket down. I have been using a Pool Noodle to tuck in the bedding so she cant undo the made bed.
This bed wedge has solved the problem AND is a vast improvement to the Pool Noodle!
The Cal King pillow fits perfectly. The foam is firm enough to stay put and fill the gap, yet it is soft enough to be cushy.
The cover is well made, and it is removable (via a zipper)machine washable.
It arrived in a very small box, well packaged. It sprung to the final size in a short time. No funny, unpleasant odor to air out. Ready to go.
I am pleased with this product and I would recommend it to friends and family.