On their free ends, they are provided with {HEAD ~ inwardly projecting snap noses} which engage a recess of {TAIL ~ the sabot} 
On their free ends , they are provided with { HEAD ~ inwardly projecting snap noses } which engage a recess of { TAIL ~ the sabot }
OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL