{HEAD ~ A window unit frame} is received in each clear window opening supported by and electrically connected to {TAIL ~ the frame} 
{ HEAD ~ A window unit frame } is received in each clear window opening supported by and electrically connected to { TAIL ~ the frame }
HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL