Kev sib dhos kab-hom txhua yam kev tsim tawm thiab ntim khoom, siv rau cov khoom noj, tshuaj, tshuaj txhua hnub, kho vajtse, teeb pom kev zoo, rooj tog thiab lwm yam kev lag luam (hnab, lub raj mis) cov khoom lag luam (sau), tshuab sealing, coding.
Feem ntau suav nrog: kua (muab tshuaj) ntim tshuab, hauv ncoo ntim tshuab, tshuab ntim kab rov tav, tshuab ntim ntsug, tshuab cov hmoov ntim ntim rau lub tshuab, kom lub hnab ntim tsis siv neeg ntim tshuab, khov khoom ntim tshuab tsis siv neeg ntim.