Flying insects, such as mosquitoes, biting flies, and moths, are naturally drawn to light. Without the bulbs, flying insects are more likely to become a nuisance at any outdoor gathering. Keep your Dynatrap models DT250IN, DT300IN, DT1000-12V, DT1050, DT1100, DT1125, DT1200, DT1210, DT1250, and DT1260working as powerfully as possible with fresh, replacement bulbs. Each bulb continues to provide insect-attracting power for approximately 3,000 (around 4 months). Each package comes with one 7-watt UV bulb keep your Dynatrap Insect Trap operating to its fullest potential. Flying insects like mosquitoes, biting flies, and moths are naturally attracted to light, which is why it's so essential to have replacement bulbs on hand in case one unexpectedly goes out leaving you unprotected. These replacement UV light bulbs fit most ½ acre Dynatrap Insect Trap Models DT250IN, DT300IN, DT1000-12V, DT1050, DT1100, DT1125, DT1200, DT1210, DT1250, and DT1260. Each bulb lasts for approximately 4 months or 3,000 hours of use. Every replacement bulb package comes with one 7-watt UV replacement light bulb.