Ryobi ONE+ 18V power tools use lithium ion battery packs. See "Notes on Lithium Ion Battery Packs" section in the "Power Tools Battery Conversion Guide" page.
As of this writing, there is no direct battery converter for Ryobi ONE+ 18V battery Pack to Craftsman C3 19.2V power tool.
Ryobi ONE 18V Power Tools Battery Conversion Guide · Stanley 18V Li-Ion Power ... Worx 20V MAX Power Share Power Tools Battery Conversion Guide · Worx 20V MAX ...
Power Tools Battery Conversion Guide. 18-Volt / 20-Volt Systems. Bauer 20V Power Tools; Craftsman C3 19.2V Power Tools · Craftsman V20 Power Tools; DeWALT 20- ...