The J shaped end of the second shield is of {TAIL ~ a complementary configuration} receivable slidably within {HEAD ~ the first J shaped end} 
The J shaped end of the second shield is of { TAIL ~ a complementary configuration } receivable slidably within { HEAD ~ the first J shaped end }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD