a portable measurement device configured to be placed in the pathway of the movable barrier and have contact with the movable barrier when the barrier is moved, {TAIL ~ the portable measurement device} including an interface and {HEAD ~ measuring circuit} 
a portable measurement device configured to be placed in the pathway of the movable barrier and have contact with the movable barrier when the barrier is moved , { TAIL ~ the portable measurement device } including an interface and { HEAD ~ measuring circuit }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD