There is no option for 0 or negative or else i would have given that. It is utter garbage for the price that I paid at that time. Highly not recommend to buy. It’s completely false branding as its neither 8” nor memory foam. It feels like cheap synthetic material and grew hardly up to 5” even after resting it for 2 days in a corner, untouched. My 40 second hand mattress was leagues beyond this one and it lasted for more than a year and a half and twice the width.