In {HEAD ~ the linear version}, {TAIL ~ the power transfer shaft} is attached to a piston head 
In { HEAD ~ the linear version } , { TAIL ~ the power transfer shaft } is attached to a piston head
OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH