A second bubble element is mounted in {HEAD ~ the central region} of {TAIL ~ the level housing}, and the bubble element is parallel to the length of the housing 
of
A second bubble element is mounted in { HEAD ~ the central region } of { TAIL ~ the level housing } , and the bubble element is parallel to the length of the housing
OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH