ULTRACEL; Ultracel pillows are soft and comfortable. They are made of synthetic fibers that are similar to silk which makes the pillow feel just as luxurious as feather pillows even though the fibers are all manmade. The pillows retain their shape over time as compare to some pillows that become flat or limp.
NEXT DOWN; DOWN and feathers are different as Down will not poke through the duvet as feathers will. The "stalk" of the feathers are thicker, longer and tougher and act like needles through the fabric.
As down alternative is synthetic, you can wash it in the washing machine.