Npuas qhwv yog cov khoom siv pob tshab pob tshab siv los ntim cov khoom tawg yooj yim. Tsis tu ncua spaced, protruding air-filled hemispheres ( npuas) muab cushioning rau cov khoom tawg yooj yim.
Cov npuas tuaj yeem ua me me li 6 millimeters (0.24 ntiv tes) hauv txoj kab uas hla, kom loj li 26 millimeters (1.0 inch) lossis ntau dua, los muab cov qib ntxiv ntawm kev poob siab thaum lub sijhawm thauj mus los . Cov npuas loj tshaj plaws yog 1 centimeter.[5] Ntxiv nrog rau cov qib kev tiv thaiv muaj los ntawm qhov loj ntawm cov pa npuas hauv cov yas, cov khoom siv yas nws tus kheej tuaj yeem muab qee hom kev tiv thaiv rau cov khoom hauv nqe lus nug. Piv txwv li, thaum xa cov khoom siv hluav taws xob rhiab heev thiab cov khoom siv, ib hom npuas qhwv yog siv cov yas los tiv thaiv zoo li qub uas cuam tshuam cov nqi zoo li qub, yog li tiv thaiv cov khoom siv hluav taws xob zoo li qub uas tuaj yeem ua rau lawv puas tsuaj.
Yog tias koj tuaj yeem muab peb cov npuas thiab zaj duab xis txheej ntawm koj lub hom phiaj cov khoom, peb tuaj yeem pom zoo rau koj cov qauv tsim raws li.
