Tumbler Tart re-scenting kits are sold individually in a 15ml dropper bottle! To be used only with our Tumbler Tart dryer balls or other dryer ball products. 15 ml will last over 100 Dryer cycles! For strong scent, use up to 5 dryer balls. Do not exceed 2 or more for cloth diaper use on synthetic materials in case of buildup. Use on low heat to keep your dryer ball lasting longer! Disperse scent as desired for light or strong scent. Pthalate Free and Dioxin Free!