Flat top or button Top batteries?

[RoyWalker]

I bought the SF501B 445nm - 1W. :beer:
It takes TWO 18350 batteries.
Does anyone know, will it take flat top or button top?
(I plan to buy the purple efest)

 

[Pi R Squared]

You need button top.

Alan

 

[RoyWalker]

Thanks.