Electronic UV fly killers work to reduce the number of flies in an area. These devices are most effective if they produce light in the 330- to 350-nanometer range to attract insects. Some devices electrocute insects as they pass through the electronic grid, and others trap them on a glue-board.
Lamps require annual replacement as they loose their effectiveness over time. The devices are most effective if placed away from outdoor openings to prevent attracting more flies into the space. Units with electronic killing boards require regular cleaning of the grid and emptying any catch trays. The glue-board fly killers require regular replacement of the board.