{HEAD ~ Combination} 1, wherein {TAIL ~ the Shore D hardness} of the plastic material is approximately 15 25 
wherein
{ HEAD ~ Combination } 1 , wherein { TAIL ~ the Shore D hardness } of the plastic material is approximately 15 25
HEAD HEAD HEAD HEAD HEAD OTH OTH REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH