They OK.  When I attached one of these to my zapper with a plastic tie, it seem to work very well the 1st night.  No good during the day.  After 1st night, the mosquito suicide seem to die down.  Each day after that, seems to get less mosquitoes. Great for June bugs. After 14 days of this, I attached another cartridge leaving the 1st one attached.  Wow, The mosquito suicide started up again, after dusk.  Again, after about the 3rd night.  Less suicides.  That's all I can say about these cartridges.  In about 14 days, I will replace a 3rd one in place with the 1st one.  I will continue to rotate the cartridges in this order. This way seems to work better.  The price with Amazon seem to be cheaper then the store.  Because they do seem to work somewhat vs nothing at all, I will continue to use them.  Without the cartridge, my zapper makes a good yard light.  I hope this helps.  These cartridges will work with any zapper, but get the plastic ties to attach them.  The sticky stick on's are junk
They OK. When I attached one of these to my zapper with a plastic tie, it seem to work very well the 1st night. No good during the day. After 1st night, the mosquito suicide seem to die down. Each day after that, seems to get less mosquitoes. Great for June bugs. After 14 days of this, I attached another cartridge leaving the 1st one attached. Wow, The mosquito suicide started up again, after dusk. Again, after about the 3rd night. Less suicides. That's all I can say about these cartridges. In about 14 days, I will replace a 3rd one in place with the 1st one. I will continue to rotate the cartridges in this order. This way seems to work better. The price with Amazon seem to be cheaper then the store. Because they do seem to work somewhat vs nothing at all, I will continue to use them. Without the cartridge, my zapper makes a good yard light. I hope this helps. These cartridges will work with any zapper, but get the plastic ties to attach them. The sticky stick on's are junk