You can expect about 2 hours to 3 hours of run time with this computer battery when new, depending on your energy use.
This Samsung AA-PL9NC6B battery replaces the Samsung NP550 R420 R430 R470 R480 RV510 RV511 R519 R520 R530 R580 R730 Q320 series and also the NP365E5C family of laptop batteries and a host more which are listed at the extreme bottom of this web page.