Description of examples or preferences is properly set forth in the specification rather than the claims. If stated in the claims, examples and preferences may lead to confusion over the intended scope of a claim. In those instances where it is not clear whether the claimed narrower range is a limitation, a rejection under 35 U.S.C. 112(b) or pre-AIA 35 U.S.C. 112, second paragraph should be made. The examiner should analyze whether the metes and bounds of the claim are clearly set forth. Note that the mere use of the phrase "such as" or "for example" in a claim does not by itself render the claim indefinite.

Examples of claim language which have been held to be indefinite because the intended scope of the claim was unclear are:

1. (A) "R is halogen, for example, chlorine";
2. (B) "material such as rock wool or asbestos" Ex parte Hall, 83 USPQ 38 (Bd. App. 1949);
3. (C) "lighter hydrocarbons, such, for example, as the vapors or gas produced" Ex parte Hasche, 86 USPQ 481 (Bd. App. 1949);
4. (D) "normal operating conditions such as while in the container of a proportioner" Ex parte Steigerwald, 131 USPQ 74 (Bd. App. 1961); and
5. (E) "coke, brick, or like material". Ex parte Caldwell, 1906 C.D. 58 (Comm’r Pat. 1906).

The above examples of claim language which have been held to be indefinite are fact specific and should not be applied as per se rules. See MPEP § 2173.02 for guidance regarding when it is appropriate to make a rejection under 35 U.S.C. 112(b) or pre-AIA 35 U.S.C. 112, second paragraph.