A blower with {TAIL ~ a filter} is mounted on the outside of {HEAD ~ the desk} and blows clean air into the compartment 
A blower with { TAIL ~ a filter } is mounted on the outside of { HEAD ~ the desk } and blows clean air into the compartment
OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH