ZL H604c batteries - flat top or button top?

Hello,

I'd like to buy batteries like on this picture (https://imgur.com/882oK7f), but since the ZL still haven't arrived I don't know whether these batteries will make good contact with the pogo/coil that the ZL has. As you can see in the picture the contact on the + side is a bit recessed, so will this be an issue with the ZL? Or should I order the same one with a button top?

thanks

Flat top works better for PoGo pins, as they form a circle and there is no pin in the center. A button top wouldn’t work, theoretically.

I see. Thank you.