Effect good design flawed

Have been staying with several of these or similar things the land circled. It acts, not immediately, but after 1-3 weeks, definitely! Individual "hard of hearing" pests there are all, people are not all the same!
But the sticking point, a design flaw, the battery bay is so narrow dimensions that you can use either Mono D or equivalent batteries with extreme effort. The removal is just as dangerous. You need a tool for levering and must be careful that do not jump the battery case in the face. The smells and looks very strong to China production, what I actually otherwise shun entirely. The price, now has nothing to do with reality.