This unit will have a fan to force {HEAD ~ air} into {TAIL ~ the hat} so that the person would not need to use energy to suction the air 
into
This unit will have a fan to force { HEAD ~ air } into { TAIL ~ the hat } so that the person would not need to use energy to suction the air
OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH