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 DT2000XL and DT2000XLP working as powerfully as possible with fresh, replacement bulbs. Each bulb continues to provide insect-attracting power for approximately 3,000 (around 4 months). Comes with four 6-watt bulbs to help you keep your DynaTrap Insect Trap operating to its fullest potential.