HartzUltraGuard Flea & Tick Collar for Dogs and Puppies - 22" Neck, 7 Month Protection (pack of 4)

I clean my dogs and sprayed my house down. I put the collars on and a few days later I found 2 fleas still.

First time I bought.these they had metal clasps and lasted for 6 months. For some reason the clasps are now plastic. Lasted three days with active dogs. Put back the metal clasps please Hartz!