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