Fiber waterbed mattresses have layers of a felt-like batting inside the mattress to absorb some of the motion associated with traditional waterbeds. Waveless waterbed mattresses have a honeycomb, or hydraulic chamber, design that controls the movement of water to reduce the waves.
Waveless waterbed mattresses are usually firm due to the coil design of the honeycomb structure. Fiber waterbed mattresses are available in a variety of firmness options; mattresses with more fiber filling are firmer.
Generally, fiber waterbed mattresses are associated with difficulty draining partly because of water absorbed by the fiber. Waveless waterbeds are considered easier to drain because the design of honeycomb does not absorb water.