alvita Description PVC hot water bottle. This partially filled hot water bottle is made of phthalate-free PVC and is suitable for people with latex allergies. Directions for use: Do not fill the bag with boiling water. Let the water cool for 5 to 10 minutes. Fill to ⅔ capacity or less. Do not overfill the bag as this may cause it to burst. Hold the bag upright by the neck, filling slowly and carefully