My father used Harris roach tablets and I have been using them for 50 years myself. They work. I’ve watched roaches eating them, seen tablets that have been nibbled on by roaches, and then I don’t see roaches for 8 months or more. When I see one I put out a few more tablets. I’ve tried other brands of roach products but none work as well as Harris products. A roach on my deck at night ran before I could kill it. I put a Harris roach tablet on the railing, turned off the light, then checked 10 minutes later and the roach was on the rail eating the tablet. They go back to their nest and die.