Cal. Code Regs. Tit. 11, § 4060 - Testing Procedures
(d)
(1) A functioning chamber load indicator must meet all of the following conditions:
(A) Explanatory text and/or graphics either incorporated within the chamber load indicator or adjacent to the chamber load indicator is/are permanently displayed by engraving, stamping, etching, molding, casting, or other means of permanent marking.
(B) Each letter of explanatory text must have a minimum height of 1/16 inch.
(C) The explanatory text and/or graphics shall be of a distinct visual contrast to that of the firearm.
(D) The "loaded" indication, that portion of the chamber load indicator that visually indicates there is a round in the chamber, shall be of a distinct color contrast to the firearm.
(E) Only when there is a round in the chamber, the "loaded" indication is visible on the firearm from a distance of at least twenty-four inches. When there is no round in the chamber, the "loaded" indication must not be visible.
(F) The text and/or graphics and the "loaded" indication together inform a reasonably foreseeable adult user of the pistol, that a round is in the chamber, without requiring the user to refer to a user's manual or any other resource other than the pistol itself.