Cov ntawv ntim khoom feem ntau muaj lub zog siab thiab toughness. Nyob ntawm cov yam ntxwv ntawm cov khoom raug ntim, nws yuav tsum tau nthuav tawm cov khoom siv tshwj xeeb- xws li dej tsis kam, roj tsis kam, dej tsis kam, ua pa, thiab cov khoom tiv thaiv kab mob.
Dej-raws li txheej txheem txheej txheem tuaj yeem siv rau hauv daim ntawv ntim khoom noj kom muab nws cov khoom xws li dej tsis kam, roj tsis kam, thiab kub- sealability, thaum tseem ua kom muaj kev nyab xeeb rau cov khoom noj khoom haus -cov ntaub ntawv sib cuag.
