Look: look at the package to see if strong enough, it must be think and strong to guarantee the tube avoid broken or loosen. It should have ready and detailed instruction manual and guide in the package. A quality insect killer must have stable and tough structure, with high quality metal which specially treated to ensure a glossy surface, dust-proof, scratch-proof, with equal color distributed. Look at the power cable and plug to see if the plastic material satisfy the safe regulation, such as the coating is too thin, and connection is loosen, etc.
Touch: The touch impression of surface with special processing would be smooth, regularity and non-scrape. There will be no abnormal sound from a strict constructed insect killer. You can try to lightly press the metal or plastic casing and outer grid, when it is easily sag means the material can be very cheap. Given the power is cut, you can also try to insert finger through the protection grid, never buy the item if you can touch any inner electrified body with your finger, because it must be extremely dangerous against international safe standard.
Small Test: Ask staff in shop to light on the item to check its operation. Check the start speed of tube be fine or not? any flicker, any fade violet color from the tube since the true UV tube must be gently and rich bright, without too much black shade. A quality insect killer must be quiet working. When the high tension grid is short by screw driver, simulate the condition it kill pest, the HPM transformer will give out stable and continue noise rapidly, with a magnetic grasping to the screw driver. On the contrary it would only sound like weak and intermittent for those low quality insect killer.
Note: the factory insect killer is a kind of small house appliance strictly requirement on the safe performance. It is not difficult to make one insect killer, but that would be much difficult for a factory to produce high quality insect killer, it needs factory to engage strong capacity to guarantee quality control. It is very important for factory be professional or not on make insect killer. Many trading companies or small workshops don't know much about quality control but they crash into the market with lower material cost for higher benefit. They don't focus on technology research or sale service, except their own profit. You will find some useful information to know more about the factory from their official web site to see if enough detail message like qualified certificate, patent certificate or full product range in their catalogue.