1. Ob chav sib nqus hmoov tswj tau, nro yuav ruaj khov

2. Tsis siv neeg 'meter', suav kev ua haujlwm nres, sub-ntim daim ntawv lo ntau dua, kom tsis txhob muaj qhov ploj lossis pov tseg

3. Ob chav rov ua dua, ntxiv rau kev ua haujlwm, txuag ntau dua

4. Hla cov ntawv sib cais, kom tsis txhob muaj qhov nplaum ua los ntawm cov ntaub nplaum tawg, kev sib txawv, sib tshooj thiab lwm yam tsis xws luag.

5. Lub riam riam, cov ntawv tawg yooj yim dua, ruaj ntseg dua

6. Retractable ntim positioning design, hloov cov niam dov thiab sub-ntim tso rau qhov nrawm dua, raug dua.

7. Tsis siv neeg laub khoom muaj nuj nqi.