The casing 2, wherein said grasping means comprise downwardly extending {HEAD ~ plate like projections} from {TAIL ~ said upper casing sidewalls} at the rear location of said upper casing 
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The casing 2 , wherein said grasping means comprise downwardly extending { HEAD ~ plate like projections } from { TAIL ~ said upper casing sidewalls } at the rear location of said upper casing
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 TAIL OTH OTH OTH OTH OTH OTH OTH OTH