The filler composition may contain {HEAD ~ a thickening/thixotropic agent}, such as {TAIL ~ silanized pyrogenic silica} 
such as
The filler composition may contain { HEAD ~ a thickening / thixotropic agent } , such as { TAIL ~ silanized pyrogenic silica }
OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL