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