The WDS-619 Groundglass Frame mounts instead of any SLW-mount in Portrait or Landscape mode.
The ground glass has marks for the current CCD sizes (40x54 /36x56 / 36x48 /33x44 mm) and includes a fresnellens.
It can be expanded with the WDS-616 Flexible Focussing Hood or the new WDS-630 Shiftable Focussing Loupe (3x)