Question: are there different size 9 volt batteries?
Answer: No, unfortunately there are very small differences in size of 9 volt batteries, even in brand name 9v batteries such as Energizer (or Energizer Industrial) and Duracell (or Duracell Procell). ... The dimensions for 9 volt batteries are H 48 mm × L 25 mm × W 15 mm (1.9 in × 1 in × 0.6 in).