Inside {TAIL ~ the collection chamber assembly} {HEAD ~ the air} is filtered, the chalk dust remaining in the collection chamber of the assembly, while filtered air is exhausted by the suction device 
Inside { TAIL ~ the collection chamber assembly } { HEAD ~ the air } is filtered , the chalk dust remaining in the collection chamber of the assembly , while filtered air is exhausted by the suction device
REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL HEAD HEAD HEAD HEAD HEAD HEAD REL REL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH