Delco M16-109 Ignition Cable Tester need battery info

[theamcguy]

I have a Delco M16-109 Ignition cable tester. It is complete in very nice shape. I need to know what size battery and voltage this tool uses. The space where the battery goes is not a standard AAA, AA, or C size. The instructions do not mention a battery. Does anybody know what size and voltage battery powers this tool. Thank you

 

[Fixr]

I have a Delco M16-109 Ignition cable tester. It is complete in very nice shape. I need to know what size battery and voltage this tool uses. The space where the battery goes is not a standard AAA, AA, or C size. The instructions do not mention a battery. Does anybody know what size and voltage battery powers this tool. Thank you

Post a picture of the battery compartment with a ruler immediately adjacent for scale.

 

[SVE Performance]

Try looking at a"B" size battery it is larger than a "AA" but smaller than a "C" .

 

[Fixr]

Try looking at a"B" size battery it is larger than a "AA" but smaller than a "C" .

I had totally forgotten about those. Kind of alphabetically obvious.