Diptyque 2.5 oz. 34 Boulevard Saint Germain Hourglass Diffuser Diptyque's Hourglass reinvents perfume for the home. Simply turn the hourglass over for a fragrant and sensorial experience. Using an ingenious process combining gravity and capillary action, the fragrance flows slowly from one glass bottle to another. Its subtle scents are then diffused, over the course of a singular hour: the Diptyque hour. Designed to diffuse its fragrance gently and slowly, the hourglass is ideal for perfuming.