You have chosen the Canon R mirrorless system but would like to use your existing lenses? This is possible.
With this adapter you can combine your M42 lenses with the camera body of the Canon R series. It should be noted that there is no transfer of autofocus control or aperture control with this combination. The subject must therefore be focused manually. Exposure control is with working aperture metering (i.e. the aperture currently set on the lens) in manual setting 'M' or with aperture priority.