The Strikeback Flea Killing Fogger is supplied in a 2-pack, as a minimum of two are often needed to treat a room. Foggers simply fill a room with an insecticidal smoke that fleas can not avoid. There is no long lasting effect, but they are the perfect way to achieve immediate control of fleas. Approved for professional and amateur use Ideal for use around the home and in roof spaces Approved for use in a work environment Contains Permethrin 12.25%w/w 3.5g fogger (x2) Always read the label before use. HSE No 8597