Tsuas yog cov ntaub ntawv sib foob ntawm cov kev txwv ntawm General, cov seals kuj xav kom pom cov nram no:
(1) kev ywjpheej thiab cwj pwm;
(2) qhov tsim nyog ua tau zoo, nrog rau lub zog tensile, elongation thiab rhuav lub zog.
(3) ruaj khov, tsis yog nyob hauv nruab nrab, thermal contraction (Joule effect) yog me me.
(4) kev ua, thiab ceev lawv cov qhov tseeb.
(5) tsis muaj kev sib qeeb, tsis txhob thab xov xwm thiab lwm yam.
Ua kom tau raws li cov kev xav tau tshaj plaws thiab feem ntau yog siv cov khoom yog roj hmab, feem ntau cov khoom siv khi sealing. Muaj ntau ntau yam ntawm roj hmab, thiab muaj ib txwm muaj roj hmab ntau yam tshwm sim, tsim thiab xaiv, koj yuav tsum to taub cov yam ntxwv ntawm ntau yam roj hmab, kev xaiv tsim nyog.