Compounds of formula (I) wherein X is chloro or bromo; Y is chloro or trifluoromethyl; and A and B are hydrogen or methyl with the proviso that one of A or B must be methyl; or the enantiomers or salts thereof, use of compounds of formula I for combating insects or acarids and for treating, controlling, preventing or protecting animals against infestation or infection by parasites, and compositions comprising compounds of formula I.