Flies are attracted by the UV light and are killed as they fly between the bars of the electrified grid within. The dead fly bodies then collect neatly in the catch tray below. They generally use more power than an equivalent glue board fly killer as the grid requires extra power.
Quality electric fly killers are carefully engineered to use enough voltage to kill smaller flies, but not so much that the bigger insects are exploded, with the resulting bits showering the surrounding area.
Look for this icon in our store to indicate an electric fly killer.