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