Salter Spiral Stair produces wood spiral staircases in a variety of wood species including oak, maple, cherry, and mahogany; other species are available upon request. The company’s solid wood spiral stair design features a unique tread attachment on a 5-in. round, solid wood center column; hardened steel fasteners are imbedded into each wood tread to create a solid characteristics. Download a product brochure at http://www.salterspiralstair.com/contractor/marketing_materials.htm. 800-368-8280, SalterSpiralStair.com.