{HEAD ~ at least one rechargeable cell} providing {TAIL ~ relatively efficient stored energy output} at both relatively high and relatively low output current levels 
providing
{ HEAD ~ at least one rechargeable cell } providing { TAIL ~ relatively efficient stored energy output } at both relatively high and relatively low output current levels
HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH