Harris Products Group Boric Acid Indoor Roach Killer with Applicator, 16 oz. (2-Pack)

works immediately and continues to work as long as the powder is down it it can be but under baseboards and put in the back of cupboards, behind refrigerators, in closets or anywhere you have had or might have a problem. I put it down around the baseboard completely around every room. then I sweep and push the powder under the baseboard. you can then mop the floor in front if you don't want have the powder get on anything else or be where a pet or child could get to it. it continues to work. the powder I put down 3 years ago is still working although I'm up a few areas and put fresh down in the kitchen and bathroom as those areas have been mopped thoroughly. although I never saw any roaches after mopping I wanted to be sure that there would not be any since my upstairs neighbor had had her apartment sprayed instead of using this powder.