Cool your whiskey faster and keep it stronger longer with this whiskey ice ball maker. Just fill bottom cup to the "fill line" with water and insert the top cup and pop in the freezer. There is an 0.010" interference over 1/16" to seal between top and bottom...an o-ring or Sugru seal may work better. Make sure to let me know how it works for you! There should be a small overflow out of the top hole. Takes about 4 hours to fully solidify. Run under warm water to help separate and release.