Cov cuab yeej mos: 5-7 xyoo (kev raug UV thiab hws ua rau cov fibers puas).
Cov phaj tawv: 10+ xyoo (tshwj tsis yog tawg lossis puas lawm).
Nco ntsoov xyuas cov lus qhia ntawm lub chaw tsim khoom kom paub hnub tas sij hawm.
Lub sijhawm tshaj tawm: Tsib Hlis-09-2025