Continue to enjoy outdoor dining and entertaining with help from OFF! mosquito lamp refills. Place these refills in your mosquito lamp and the heated diffuser will release mosquito repellant when the candle is lit. Each of the two diffuser and candle refills in this package provide up to six hours of protection so you can comfortably enjoy your deck or garden party longer. These refills are designed for outdoor mosquito lamps and should never be lit in an enclosed space.