These Dremel and Bosch batteries are functionally identical, but a piece of plastic is reversed on top, preventing them from being interchangeable. : r/assholedesign
Dremel 4300-5/40 Variable Speed Rotary Tool
Dremel Two Speed Rotary Tool Kit 200-1/15 from Dremel - Acme Tools
Dremel Rotary Took Kit Ea, 4 EA/CA - Henry Schein Medical