In addition, the internal surface of the cylinder and the external surface of the piston are grooved or keyed so as to prevent {HEAD ~ rotation} of {TAIL ~ the piston} inside the cylinder  
of
In addition , the internal surface of the cylinder and the external surface of the piston are grooved or keyed so as to prevent { HEAD ~ rotation } of { TAIL ~ the piston } inside the cylinder
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH