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