Medium Back Riding lawn mower seat. 1-hole bolt pattern 1/2 - 13 and a 22 hole bolt pattern 5/16 - 18 clinch nuts. Seat back is heavily padded and provides maximum support to the lumbar area of the operators back. 1-3/4" foam pad provides total comfort. Removable black cover. 17-3/4" wide, 11-1/2" high. (note: mounting bracket may have to modified to mount seat)