An Ashkenazi set means that the etrog has a pitom (the stigma, or pollen receptor, of the flower does not fall off when the fruit forms - it hardens into a woody stem-like protrusion at the top of the etrog. This is the traditional variety of etrog used in the Ashkenazi community. Note: If the etrog has a damaged pitom, or if it used to have a pitom but the pitom broke off, it is no longer kosher.
A Sefardi set means that the etrog grows with no pitom (see above for an explanation of the pitom). This is the traditional variety of etrog used in the Sefardi community. Note: Because this variety of etrog growns naturally without a pitom, it will likely remain kosher even if bumped or dropped.
More expensive sets will have bumpier, more wrinkled etrogim that are brighter yellow and more symmetrical. Less expensive sets may have green or green-ish etrogim with smoother peels. All sets are kosher.
Only members of the local community may order lulav and etrog sets through this form, because pickup is local and in-person. If you are not a member of the greater Oklahoma City Jewish community but wish to order a lulav and etrog anyway, please contact the Synagogue main office.