Also, {HEAD ~ the membrane} 62 completely covers the opening 60 and thus prevents {TAIL ~ the opening} from becoming clogged with grass 
prevents
Also , { HEAD ~ the membrane } 62 completely covers the opening 60 and thus prevents { TAIL ~ the opening } from becoming clogged with grass
OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH