The aluminium foil membrane may alternatively be reinforced by a grid structure inside {TAIL ~ the chamber} and across {HEAD ~ the inlet} thereto 
The aluminium foil membrane may alternatively be reinforced by a grid structure inside { TAIL ~ the chamber } and across { HEAD ~ the inlet } thereto
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH