Traits

The classic, round mouse ears.
They should be mostly circular and not oval-shaped. Maximum size of a single ear is ~the size of their head, and minimum size is ~1/3 the size of their head.

A long, thin, and smooth tail.

The windup keyhole is located in the center of the back between the shoulder blades.

Note:  If the windup key is located on the back and hidden by the character's pose, a separate reference/cutaway showing the key is required.