Xikar the american specialist in humidification offers this bottle of propylene glycol. volume: 8 oz or 236 ml you can use the xikar propylene glycol solution this solution is ready to use no need to dilute it with water. this solution automatically regulates the humidity of your cigar cellar to 70% hygrometry. it is suitable for all types of humidifiers whether crystal or foam electric or not (except cigaspa). it extends the life of humidifiers.