Please note: This text was taken directly from the manufacturer.
For years, telescope manufacturers have typically utilized two types of dovetail mounting systems. A "wide" version (such as the one used by Losmandy) and a "narrow" version (which fits telescopes made by Orion, Vixen, etc.). Unfortunately, this limited which Optical Tube Assembly could be used with your mount. Specifically if you had a telescope or tube ring system with a "wide" dovetail bar, and wanted to use our Orion Atlas EQ-G Mount which requires the "narrow" bar. With the new Wide Dovetail Saddle, your Atlas mount can be joined in harmony with its non-Orion OTA companion. Simply remove the "narrow" saddle and replace it with "wide" saddle. There are two saddles available with slightly different base components. Atlas mounts manufactured in 2009 require the #7951 saddle, whereas Atlas mounts made prior to 2009 accept only the #7950 saddle. If you're not sure which vinatge of moutn you have, simply measure the height of the declination collar with a metric ruler. For Atlas mounts manufactured in 2009, the collar is 57mm tall and will require saddle #7951. For those made before 2009, the collar is 53mm and will require saddle #7950. Both Wide Dovetail Saddles are precision machined from die-cast aluminum for long-lasting durability. The spring-loaded, split-clamp design allows the saddle to be opened wide for easy drop-in attachment of the dovetail bar. Two large knobs provide excellent grip for tightening the saddle clamp, even with gloves on.