YONGNUO External Flashlight Battery Pack SF-18: Protective Design ,Performance and Much useful Specification:it is ... (d) Net weight: 170gOperating Temperature range: 0oC-40oCSuits: Nikon SB-11, SB-20, SB-22, SB-24, SB-25, SB-26 ... without break or risk of overheating YONGNUO Flash Battery Pack SF-18N