We offer the ability to upgrade your grinder with a silky smooth finish. To achieve this silky smooth finish, we use an additive derived from Durian tree nuts, ultimately resulting in a more luxuriously smooth feel that glides rather than grips like other silicones. However, we recommend you avoid the silky smooth upgrade if: You are allergic to durian, tree nuts and tree nut derivatives or musk thistle seed You are sensitive to smell - Normal silicone has no scent however using silky smooth will give the silicone a subtle, nutty scent. The super silky upgrade is only available on our sex toy grinders and both of our made to measure penis extenders.