Standard Spiral Kit (SKD) are our most common spiral stair. It is a bolted assembly with stamped parts. The cost is comparable to a Fully Assembled welded spiral staircase. It is economical to produce and ship. There are limited options, but there are still a good variety of step baluster and handrail designs to choose from. Standard spiral stair kits are available in diameters from 40" to 72" with no height limitation. Available materials for this type of staircase are steel, aluminum, and stainless steel. Assembly of a Standard Spiral Kit stair requires two people, takes approximately 8 hours to complete, and is the most economical to ship.