This mosquito lamp lasts up to 6 hours against mosquitoes that may carry the Dengue, or West Nile viruses Maintains ambiance in outdoor spaces Activated heated diffuser that releases airborne insect repellent Enjoy and outdoor occasion with friends without worrying about mosquitoes Pack of 4 Off! Mosquito Lamp, provides a more effective solution while maintaining ambiance in outdoor spaces. It has a 6-hour duration per refill/candle, new sand core technology, and is weather resistant. The active ingredient lasts as long as the candle and allows for start and restart without loss of active. It provides 10' x 10' sqft of mosquito protection and includes 1 reusable lamp and mosquito repellent candle. For mosquito lamp refill, use #76086.