They use a UV/blue light—often running continuously—to attract flying insects to a removable sticky or adhesive cartridge. Insects stick to the cartridge, which can be removed and disposed of when full.
Most kits target flying insects such as house flies, fruit flies, gnats, mosquitoes and moths. Ultrasonic repeller kits additionally list ants, roaches, spiders and rodents among the pests they aim to deter.
Replacement intervals vary by device and manufacturer: some instructions recommend replacing the cartridge every month or when it looks full, while other product text and reviews note roughly a two-week (14-day) interval for best performance. Follow the manufacturer’s guidance and replace sooner if cartridges appear full or performance drops.
Starter kits commonly include one or more plug-in devices plus adhesive cartridges or refill packs. Offerings range from a single device with multiple cartridges to multi-device packs and multi-pack repeller sets.
Descriptions list common indoor rooms—kitchens, hallways, basements, attics, bedrooms and living rooms—and recommend placing one unit per room to provide continuous coverage.
Plug the unit near where flying insects congregate, avoid competing light sources (for example, nearby windows), plug directly into a properly functioning wall outlet (avoid extension cords or multi-plug adapters), and keep units and refills out of reach of children and pets.