An adjustable weight is provided to control {HEAD ~ the force} exerted upon {TAIL ~ a signature stack} during operation 
exerted upon
An adjustable weight is provided to control { HEAD ~ the force } exerted upon { TAIL ~ a signature stack } during operation
OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH