The metal spiral staircase details are as follows, each step is 3/4 (19mm) high giving a total between floors of 9 (22.85Cm). You can reduce or increase the height of the staircase by adding or taking away the footsteps.
You will need some tools to finish the kit, such as a modeling knife, small file, and drill bits. The kit can be glued using super glue or epoxy resin even soldered and comes as unpainted.
Full instructions in each Kit.