They must go to the Post Office to Sign for the letter and pick it up. If no one picks up the letter after 5 to 7 days, USPS will leave a second delivery notice. Again the delivery slip reminder is left by the letter carrier. Finally after 5 to 7 days the third and final delivery attempt is made to the delivery address.
Gamma-cyhalothrin is a single stereoisomer of the pyrethroid insecticide cyhalothrin, and as such shares physical, chemical, and biological properties with both cyhalothrin and lambda-cyhalothrin, which are mixtures of 4 and 2 isomers respectively.
Cyfluthrin is a pyrethroid insecticide and common household pesticide. It is a complex organic compound and the commercial product is sold as a mixture of isomers. Like most pyrethroids, it is highly toxic to fish, invertebrates, and insects, but it is far less toxic to humans. It is generally supplied as a 10-25% liquid concentrate for commercial use and is diluted prior to spraying onto agricultural crops and outbuildings.