At 2000 ug/mL in Methanol. Standard contains: Benzene, 1,2-Dibromoethane, 1,2-Dichloroethane, Ethylbenzene, Isopropylbenzene, MTBE, Naphthalene, Toluene, o-Xylene, m-Xylene, p-Xylene. Stores refrigerated. A NIST traceable reference material. 1.5mL ampule