Dab tsi yog U-bolt

U-bolt, tseem hu ua eeb ntsia liaj qhov rooj hauv lus Askiv, yog ib qho khoom siv tsis zoo uas muaj npe tom qab nws cov duab U-shaped. Nws muaj cov xov ntawm ob qho kawg uas tuaj yeem ua ke nrog cov txiv ntseej thiab feem ntau yog siv los kho cov khoom siv tubular xws li cov kav dej lossis cov ntaub ntawv xws li lub tsheb nplooj ntoos hlav. Vim nws cov khoom ruaj khov zoo li tus neeg caij nees, nws yog hu ua eeb ntsia liaj qhov rooj.
Cov duab tseem ceeb: semicircle, square, txoj cai kaum, daim duab peb sab, oblique daim duab peb sab, thiab lwm yam.