As you might guess by our ordering the refills, the trap is working well.  We don't have a huge flea problem but it attracts them.  Our only kitty is almost 18 and has weakening kidneys, so the toxicity in the blood now attracts fleas.  We've never had fleas with any of our cats other than this one and another many years back that had the same kidney issues when he got old.  And we never used any chemical flea prevention poisons on them either.  Just food that's real food and not full of fillers and dead and diseased animal parts.