I do buy industrial strength pesticides on Amazon but apparently if you were to buy off a reputable supplier you'd need to give your exterminator credentials. I

I do buy industrial strength pesticides on Amazon but apparently if you were to buy off a reputable supplier you'd need to give your exterminator credentials. I spray Bayer's Polyzone outside and use Tempo between walls/floor and cabinets and see a dead roach inside every quarter or so (there are commercial food establishments nearby so roaches are just roaming the streets). Never bothered with GHI as the pesticides already do a great job.