Dab tsi yog qhov laj thawj tseem ceeb rau kev xeb ntawm cov hlau yeeb nkab fittings?
1. Cov txheej txheem txheej txheej ntawm cov yeeb nkab hlau fittings raug puas tsuaj vim kev sib tsoo thaum lub sij hawm thauj mus los.
2. Cov txheej sab hauv thiab sab nrauv raug puas vim kev sib tsoo thaum lub sij hawm hoisting.
3. Kev puas tsuaj rau cov hlau yeeb nkab fittings thaum siv.
4. Kev puas tsuaj tshwm sim thaum rov ua dua.
