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