DD you just failed and fitted bogus parts!
Uses standard Duracell® batteries Is a cut and paste.
If you use any other brand than Duracell like Energizer they are not approved.
Duracell and Artex must have agreed standards and QA in place with appropriate FAA approval. ( Aircraft Timex wheel bearing have the same part number as the commercial ones - but only certain production runs get Aviation approval and paper work - only due to high batch level quality checks than the other production runs).
In the Boing is it a type and model "megaphone"? I assume it is as certain specs will be required to be meet such as volume.
How to Make a Megaphone With Construction Paper | eHow