Lub aperture ntau ntawm cov pellet zeb tuag siv rau cov khoom ntoo pellet yog nyob nruab nrab ntawm 5.0-18.0mm, thiab qhov ntev-aperture ratio, los yog compression ratio, yog nruab nrab ntawm 1:4-1:10.
Lub compression piv ntawm lub nplhaib tuag rau lub cav ntoo pellet yog txiav txim siab raws li cov khoom siv raw.Lub compression piv ntawm cov khoom sib txawv yog txawv, cov ntaub ntawv nyuaj, cov compression me me;lub fluffier raw cov ntaub ntawv, qhov loj compression piv .Yog hais tias, cov fluffier raw cov ntaub ntawv yog yooj yim dua rau nias thiab daim duab, cov fluffier raw cov ntaub ntawv muaj fiber ntau, uas muaj fiber ntau cov ntaub ntawv yog ib qho yooj yim mus tsim cov duab.