I just want to stick this here in case anyone ever has a similar problem, and finds this via the search function.
My CT screwdriver is the Ultimate Edition 10th Doctor Season 3-5 one and it takes AG5, 393 button cell batteries.
I discovered that different brands make these in slightly different sizes, when I bought a bunch by T&E brand and found them to be slightly slimmer so they didn't work. The brand that CT uses (which fit) is Tianqiu and they're sourced very cheaply in bulk on eBay. I just got 100 shipped internationally for $8.
My CT screwdriver is the Ultimate Edition 10th Doctor Season 3-5 one and it takes AG5, 393 button cell batteries.
I discovered that different brands make these in slightly different sizes, when I bought a bunch by T&E brand and found them to be slightly slimmer so they didn't work. The brand that CT uses (which fit) is Tianqiu and they're sourced very cheaply in bulk on eBay. I just got 100 shipped internationally for $8.