An electronic cigarette vaporiser operable in a 'discrete' mode to reduce the amount of vapour produced, compared to a normal mode. The 'discrete' mode may cause the vapour produced to be less visible or noticeable. A button or sensor on the vaporiser, a case for the vaporiser or a connected smartphone may control the change between the two modes. The discrete mode may reduce the power delivered to the atomiser； vary the duty cycle, frequency or other parameters of the signal that powers the atomiser, which may be a pulse width modulated signal； reducing the temperature of the heating element； or vary the ratio of vegetable glycerine to propylene glycol in the e-liquid. The vaporiser may comprise lights to indicate the amount of e-liquid consumed, and may dim these lights to indicate the discrete mode is active. The e-cigarette may have a square or rectangular cross-section with rounded corners. The vaporiser may be filled from a cartridge when placed in a re-fill case, possibly using a piezo-electric pump. Also disclosed is a portable storage and carrying case adapted for a refillable personal vaporizer and that refills and recharges the personal vaporizer.
