heavy bag

Hi i would like to know what size heavy bag to get. I am new to boxing around 5'11' 150 I am in fairly good shape. Im just not sure what is better between 60 to 100 lbs

i use 120 because its good for training up your wrists but you are lighter than me so i would say toward the lighter side probably 80 pounds... are you buying a bag or trying to stuff one yourself???

I was thinking of buying a champion bag at a local store thanks for the advice