9th Cir. Model Jury Instr. (Civil) 15.12

For a product’s design to be protected under trademark law, the design must be non-functional.

[A product may be functional in either of two ways. They are referred to as “utilitarian functionality” and “aesthetic functionality.”]

A claimed trade dress has [utilitarian] functionality if it is essential to the use or purpose of a product or affects its cost or quality. To determine whether this definition is satisfied, you should consider the following factors:

(1) whether the design yields a utilitarian advantage in how well the product works;

(2) whether alternative designs are available;

(3) whether advertising touts the utilitarian advantages of the design; and

(4) whether the particular design results from a comparatively simple or inexpensive method of manufacture.

No one factor is dispositive; all should be weighed together.

[A claimed trade dress has aesthetic functionality if it serves an aesthetic purpose wholly independent of any source identifying function, such that the trade dress’s protection under trademark law would impose a significant non-reputation-related competitive disadvantage on its owner’s competitors. The inquiry is whether, if one seller were given exclusive rights to use the claimed trade dress, other sellers would be forced to use alternative designs that make their products more costly to sell, or for which consumers’ willingness to pay would be lower for reasons having nothing to do with the reputation of any source (e.g., the alternative designs would not have as much intrinsic aesthetic appeal).]

[The plaintiff [name] has the burden of proving non-functionality by a preponderance of the evidence [to show that the trade dress is valid and protected from infringement].]