The Nemesis CM will kill the insects by electrocuting them as they fly through a high voltage metal grid situated adjacent to the bulbs. As they come into contact with the grid, the current passes through the insect, instantly killing it. The dead insect is caught in a tray suspended immediately below the unit.

These types of units are usually a better choice for large areas such as food processing plants, factories and supermarket warehouses. They should be used to guard the entry points shuch as doorways, receiving and shipping bays and garbage areas. This is because they have a much higher capacity than insect light traps and can deal with higher levels of infestation. They should not be used inside a building where there is open food or sensitive areas. They have shatterproof bulbs for 'non-glass' areas in the food industry and splash-proof models should be used in 'wet areas' such as slaughter houses, dairies, fish docks and garbage areas.

Historically it has been felt that the killing grid used in insect electrocutors fragment flies and this type of unit should be avoided. This was true of some of the earlier lower cost models. However, new design technologies utilized in AC powered models ensures that long-term reliability is achieved., insect shatter minimized and 'first time' killing rate increased.