Newel stairs are a particular type of spiral stairs. They are constructed with a central newel (a pillar made of steel or stainless steel) instead of a central stair well. The step treads of newel stairs are fixed to this pillar. Because of low space requirements and their visual elegance newel stairs are mostly used as residential staircases for apartments covering two storeys. Often they also lead to an integrated gallery. If an adequate flight width is considered, it is of course possible to construct a newel staircase as main stairs.