Dolle Graz Modular Staircases &ndash; Stairway Kit 12 Treads 95"H - 115"H - Black Perfect modular staircase for frequent use in confined small areas. Indoor Use Only. Easily installaed in one day using common tools. Directions and support available if necessary. Adjustable Height 95" to 115"H Various staircase layout options available. One year warranty.