An upper case having {HEAD ~ an insulated inner surface} including a sidewall structure complementary to the lower case sidewall structure forms {TAIL ~ a lid} for the channel and is insulated from the lower case 
An upper case having { HEAD ~ an insulated inner surface } including a sidewall structure complementary to the lower case sidewall structure forms { TAIL ~ a lid } for the channel and is insulated from the lower case
OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH