independant wdog timer cubemx parameters

hello every body , i succeeded to  use indep watchdogtimer on stm32f103cb using cubemx 

just i have one question :

clock prescaler affects the timout on which the watchdogtimer will restart so treset the system here 32 means 3276.8 ms 

, so what is the role of 4095 downcounter  reload value 0xFFF , why in cube i can change it what will it affect in the working of watchdogtimer timing ???