{HEAD ~ At least a portion} of the catch is positionable around at least a portion of {TAIL ~ the tab} 
{ HEAD ~ At least a portion } of the catch is positionable around at least a portion of { TAIL ~ the tab }
HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL