30 CFR § 20.6 - General requirements.
(a) The lamps shall be durable in construction, practical in operation, and suitable for the service for which they are designed and approved.
(b) The intensity of light, distribution of light, and battery capacity shall be adequate for the use for which the lamp is intended.
(c) Battery terminals and leads therefrom, as well as the battery gas vents, shall be designed to minimize corrosion of the electrical contacts.
(d) Bulbs and other replacement parts of the lamps shall be adequately marked as a means of identification.