This mask is made for those with oily skin, but I don't find it helps with blackheads, maybe because mine are extra stubborn. Well this lasts quite a while, considering it shouldn't be used everyday!! When this is applied, it gives a very cooling experience and you know its ready to be washed off when it stiffens. It helps reduce oils for sure, but if you have dry-ish skin, this is not recommended, unless a very moisturizing lotion is used afterwards. The lid underneath the top (picture) is there to help it not dry out, afterall, it is clay so keep it there or else it would last only 2-3 days!