Mackwell 2 Cell Emergency Battery Stick. NiMH (Nickel Metal Hydride) 4AH Stick. The nominal voltage is 2.4v. Additional technical specs are: cell temperature range 0 to +40°C. Product dimensions L176mm x W27mm x H21mm. Fixing points 166mm, cable length 400mm. This battery is normally used in emergency light fittings that use a 4-8w miniature T5 tube.