Many other manufacturers used the Gino Rossi lever group on their "Leva" AL67 models to avoid having to research, design and manufacture a similar group of their own. Check for corresponding parts from the diagrams provided with your existing machine to be certain this is the correct o-ring.
This version gasket is in fact quite antiquated, and all manufactures now recommend the flat version as it provides a larger surface area for sealing.
Other manufacturers that have used the group that use this o-ring include: Bezzera, Brasilia, Faema, La Pavoni, Nuova Simonelli, the PRE-2012* versions of Victoria Arduino Athena (distributed by Nuova Simonelli, as opposed to the original antique Arduino) and Wega.
*Nuova Simonelli revised the Athena group head for models manufactured after 01/17/2012 to use a square gasket, not currently available through Espresso Parts.
Attention CA Residents: Prop 65 Warning
WARNING: This product can expose you to chemicals including lead, which are known to the State of California to cause cancer, birth defects, or other reproductive harm. For more information, go to www.p65warnings.ca.gov.