Solid Ash wood frame finished in Danish oil. Includes aluminum monorail design, home use warranty and GX Program Monitor. The WaterRower Natural is hand crafted in solid Ash and stained Honey Oak for consistency of color. Each machine has been hand finished with Danish Oil providing a deep lustre and warmth to the wood. Wood has been chosen due to its marvelous engineering properties, primarily its ability to absorb sound and vibration thus enhancing the WaterRower’s quietness and smoothness of use. Ash, like all woods used in WaterRower construction, is a premium hardwood with incredible longevity and dimensional stability. For reasons of ecology, all our woods are harvested from replenishable forests.