The Rectangular airCORE Bolster features a lighter weight form, firm cushion, and a machine washable microfiber cover that is velvety soft to the touch. Using airCORE technology (a proprietary core of air-filled pockets constructed from post-consumer recycled plastic and 100 ...The Rectangular airCORE Bolster features a lighter weight form, firm cushion, and a machine washable microfiber cover that is velvety soft to the touch. Using airCORE technology (a proprietary core of air-filled pockets constructed from post-consumer recycled plastic and 100% cotton), the bolster weighs significantly less than standard bolsters and retains shape and firmness.