cov poly hlau feem ntau yog thauj ntawm poly hlau reel, cov poly hlau yuav raug coj tawm ncaj qha. yog li nws yog qhov yooj yim los siv cov xov hluav taws xob poly no ntawm poly hlau reel rau kev teeb tsa laj kab hluav taws xob.