Shredded memory foam. Not sure what it is, but every other pillow keeps me tossing and turning. I'd give down another try. Usually squishes too flat during the night though.
I bought some shredded memory foam off of Amazon and was really disappointed. I think a lot of the reviews are very personal or their robots. It was hands down the worst pillows I've ever owned and I bought four of them because the reviews were so good. it's also possible that I just bought a cheap one because his Amazon and mass produced and what not. They got really lumpy and gave me and my wife (very different sleepers) neck pain.
I love the feel of down but I also hate that they go so flat. A good down pillow will last 15 years while down alternative is 5 or less. even though it cost a lot more it's worth it in the long run.
Not saying anybody should just run out and buy a down pillow but if that's what you're after I would say the parachute brand is the only one that I would tell people to check out right off the bat. They come in different firmness and it's easy to return them. I bought two down pillows from West elm and despite the fancy brand they were not very good and had all the same problems. Only average build quality and were flat halfway through the night. Had to have two just to get the combination of that down feel with enough support.