This “part straightÐpart spiral” stair provides another solution for special entrance, exit, or well opening requirements. Minimum well opening 36" x 72". Makes approximately one quarter turn from top to bottom. 11 risers adjustable from 7'6" to 8'0". 12 risers adjustable from 8'1" to 8'8". (Shown) 13 risers adjustable from 8'9" to 9'5". Installs either right or left hand up. Top four treads, straight section, are a welded unit. Metal treads pre-drilled to accept wood coverings. Many accessories available. Please Note: Wood tread coverings should be used with this Kit. For interior use, oak and flakeboard tread coverings are available as an option. You can also cut your own tread coverings by using the paper template furnished on request. Before ordering this stair, be sure to check your local building code. Also, please call us to make certain you have necessary headroom.