Browse through an assortment of fly killer tubes suitable as replacements for our fly killer units. From U type, circular and straight shatter-resistant bulbs in a variety of different lengths, 1env's choice of replacement bulbs will keep your machine operational. Ultraviolet Light (UV), the light that attracts flies to your unit, reduces output over time and needs to be replaced. Electric fly killers work by replicating natural daylight using UV, but changing the UV bulbs every 12 months is recommended to maximise performance.