Earbud speaker drivers for DFRobot DFPlayer Pro

I bought basic wired earbuds from a supermarket, took them apart, and connected them directly to the DACR and DACL (and GND) connections on my DFPlayer Pro. They worked well.

I would like to buy the bare earbud speaker drivers (without the earbud housing) for this, but need to know what to look for, as I don’t know what specifications to search for. There’s very little info on the packet of the ones I bought.

Is anyone able to assist?