Below prices are for units that are 7 to 9 feet, floor-to-floor, 3 1/2, 4 or 5-foot diameter. We advise 5-foot diameters for all staircases where possible. 5' diameter, 30 degree tread will fit most building code requirements. For spiral staircases, of course, we advise application and consultation with local building authority. All our staircases are built custom to your requirements. Delivery time is about 6-8 weeks from receipt of deposit.