Airless pumps use a vacuum system which suctions product out of a plastic bottle, without the need for a tube. When the pump is pressed down, a plastic piece in the bottom of the bottle is pulled up, bringing the product (usually a cream base) out through the pump. Airless pumps don't need to be unscrewed by the customer because the airless technology can suction out all of the product.
Stock colors are typically white or black, with clear overcap included.
Unlike pump caps and spray caps, airless pumps are made entirely of plastic. As long as all the components are made from the same type of plastic (usually PP), these caps can be recycled with the same type of plastic.