Feem ntau, txoj kab uas hla ntawm cov yeeb nkab uas peb nquag tau yog 76/89 / 114mm. Yog tias tus neeg yuav khoom muaj cov yeeb nkab nrog qhov tshwj xeeb, peb kuj tuaj yeem txo qhov taub kom tau raws li qhov xav tau. Hauv kev tsim cov txheej txheem ntawm cov kauv qhwv nrog cov txiv ntoo koob, ua ntej peb yuav tsum tau yuav cov khoom siv raw. Rau zus tau tej covntsia hlau txuasyeeb nkab, peb muaj 6 meters ntev thiab 12 meters ntev, feem ntau 6 meters.
