{HEAD ~ The detector} includes {TAIL ~ a microswitch} having a sensing arm which contacts a center portion of an elastic membrane 
includes
{ HEAD ~ The detector } includes { TAIL ~ a microswitch } having a sensing arm which contacts a center portion of an elastic membrane
HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH