yet provide the same rise and thus adjustable bottom bolt 210 is provided adjustable height device 216 which is different from the overall unit is seen but is clearer in later diagrams this part of the tread support allows the overall adjustment of heights on all the steps not just on the bottommost step this part of the invention the adjustment device 216 is seen to comprise two sets of holes on two different portions of the device the holes overlapping in a number of configurations which allow different heights to be maintained and a fastener which may pass through the selected pair of holes one unit of the invention may have a plurality of such height adjustment devices 216 thereon in the presently preferred embodiments the number is four however more may be used for extra support or fewer may be used if it may be safely accomplished all within the scope of the present invention fig3 is a front view of the device in use on a set of stairs the stringer cannot be seen but stairs 300 have tread 304 which is held in place by tread support 306 again bottom tread support 308 has bottom bolt.