{HEAD ~ A stair cleaning device} intended for cleaning the steps and {TAIL ~ risers} of stairs and other confined areas comprises three heads driven by a motor and a belt and pulley system 
intended for cleaning
{ HEAD ~ A stair cleaning device } intended for cleaning the steps and { TAIL ~ risers } of stairs and other confined areas comprises three heads driven by a motor and a belt and pulley system
HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL REL OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH