Alternatively or in addition to the strap, tray or holder 32, the casings 14 may have {HEAD ~ an attachment means} for directly attaching {TAIL ~ one casing} 14 to another 
Alternatively or in addition to the strap , tray or holder 32 , the casings 14 may have { HEAD ~ an attachment means } for directly attaching { TAIL ~ one casing } 14 to another
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 REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH