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