Cov kav hlau tsis muaj seamless rau kev khawb thee
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Cov kav hlau tsis muaj qhov sib txuas rau kev khawb av thee - GB / T 17396-2009
Cov yeeb nkab hlau tsis muaj seamless rau cov thee tsuas yog siv los tsim cov yeeb nkab tsis muaj seamless rau
hydraulic prop hauv thee mine.
