Various embodiments of the invention provide {TAIL ~ an apparatus} of the kind mentioned at the outset, which presents a lowest possible total weight and {HEAD ~ a low energy demand} 
Various embodiments of the invention provide { TAIL ~ an apparatus } of the kind mentioned at the outset , which presents a lowest possible total weight and { HEAD ~ a low energy demand }
OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD