DetailsTetraSan has both contact and translaminar activity, providing up to 28 days of control from a single application. The mode of action of TetraSan is as a chitin synthesis inhibitor. Chitin is the essential component of a mite's exoskeleton. TetraSan causes chitin to become brittle and thin and, as a result, mites die when attempting to molt from one life stage to the next. Be sure to read the TetraSan label for usage directions and safety warnings.