I urge you to read this, even the hartz brand collars caused problems. They can also be dangerous to children who come in contact with them.
Popular flea collar linked to almost 1,700 pet deaths. The EPA has issued no warning.
Since Seresto pet collars were introduced, the EPA has received more than 75,000 reports related to the collars, including 907 involving human harm.
Read in USA TODAY: https://apple.news/A78_uo4GjQWq_FP9GTVxg9w