Badaptor DEW-RYO - 18V battery adapter compatible with DeWalt batteries. For use on Ryobi 18V tools.: Amazon.co.uk: DIY & Tools
DM18RL Battery Adapter for Ryobi 18V Power Tools, Adaptor Convert for Dewalt & for Milwaukee M18 Convert for Ryobi 18V Power Tools: Amazon.co.uk: DIY & Tools
3D Printed DeWALT Battery Adapter for Ryobi Tools - YouTube
Battery Adapter For Ryobi 18V Li-ion Battery Convert to for Dewalt 18V Tools New | Stephen Franks