Also provided are {HEAD ~ plates} to form {TAIL ~ zigzag air passages} by blocking a space between the inner cover and the outer cover 
to form
Also provided are { HEAD ~ plates } to form { TAIL ~ zigzag air passages } by blocking a space between the inner cover and the outer cover
OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH