How deep is the Purple™ Mattress Protector? The Purple™ Mattress Protector protects mattresses up to 15 inches tall! Related articles Does Purple™ Mattress Protector protect against bed bugs? What is the Royal Seat Cushion return policy? Does the Purple® Mattress protect from liquid? What kind of mattress protector do I need? Do the Purple adjustable bases work with any Purple mattress?