Chemical name: from racemate (S) -α-cyano-3-phenoxybenzyl- (1R, 3R) -3- (2,2-dichlorovinyl) -2,2-dimethyl ring Propane carboxylate and (R) -α-cyano-3-phenoxybenzyl- (1S, 3S) -3- (2,2-dichlorovinyl) -2,2-dimethylcyclopropane carboxyl Ester composition