{HEAD ~ A stair cleaning device} 6 wherein the area swept by the cleaning heads on rotation of the disc is {TAIL ~ a circle} having a diameter of about 200 mm 
{ HEAD ~ A stair cleaning device } 6 wherein the area swept by the cleaning heads on rotation of the disc is { TAIL ~ a circle } having a diameter of about 200 mm
HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH