Thus, {HEAD ~ the present invention} can be implemented with either a compression spring or {TAIL ~ a tension spring} 
Thus , { HEAD ~ the present invention } can be implemented with either a compression spring or { TAIL ~ a tension spring }
OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH REL REL OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL