Before Use: You are recommended to wash it before use, or some suggest to put it into oven for 3-5 minute. Step.1 Close the tray and try to lock the groove on the side of each skull Step.2 Fill in the skull with water from the top hole, sure you can make fruit jello or chocolate skull too Step.3 Put it in the refrigerator for about six hours. Then that finish. Make the ice "diamond" out and enjoy it. User Tips: When you use ice cube molds,Use boiled water or distilled water are better than tap water for making a perfect crystal clear 3D ice cube. Temperatures range: -40°F~450°F/-40°C~230°C Size : 4.72" x 3.35" x 1.97" (12cm x 8.5cm x 5cm) Skull Size : 1.57" x 1.77" (4cm x 4.5cm) package: 2 Pack Can make 8 Pcs skull ice molds