In a first embodiment the apparatus is formed by two separate units, each consisting of a mounting plate and two connection arms, or one unit comprising two connection arms and {HEAD ~ the other one} comprising {TAIL ~ one connection arm} 
comprising
In a first embodiment the apparatus is formed by two separate units , each consisting of a mounting plate and two connection arms , or one unit comprising two connection arms and { HEAD ~ the other one } comprising { TAIL ~ one connection arm }
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 OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL