a cylinder and {TAIL ~ piston} forming {HEAD ~ a chamber} mounted on a drop vehicle; and 
a cylinder and { TAIL ~ piston } forming { HEAD ~ a chamber } mounted on a drop vehicle ; and
OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH