This polyester fiber filling has an ideal density for speaker construction, occupying minimal internal volume while enhancing the fullness of the bass. | It effectively prevents most high-frequency sounds from escaping through the speaker's port, providing excellent isolation for high-frequency sounds. | In addition to using it for regular speaker construction, you can also apply it to car audio installation and repair. | It is very skin-friendly, allowing direct contact without causing itching or inflammation. | It has excellent fire-resistant properties and will gradually extinguish after being removed from an open flame.