One reviewer wrote of a failure but also from the fact that the "bait feed" was in front of the case and in the entrance area sown.
This is in my opinion the error:
Mice are very sensitive and if the cold metal on which they collect piece by piece feed "wobble" (in which case you get a "rocker mechanism") then the scares these shy creatures probably from.
Therefore: highly tasty bait in the trap and at the "point of no return" interpret.
Up event in a safe place close to the wall, then it is without question a very well-functioning case.
An application tip for particularly prudent mice in good demarcated areas (eg rooms whose door you can simply close):
Increase studies and reproducible experiences have shown that the impulse for the mammals usually are willing to forget all caution, and even "seeing eye to race in the fall" is the thirst.
If you have mice in a confined area where you can make sure that they find no water, can be served outside the trap chips, bacon or other "Salzigkeiten".
IN the case then comes tomato, melon, ... something to "drink" halt.
Erfahrungsgenmäß go to the trick even rats in the dussligesten wire box traps.