Idaho Code § 54-2618: Certificate to be displayed and certificates of competency and registration carried or in vicinity of work site.

All holders of valid certificates in the contractor and specialty contractor classifications shall display a sign or card, upon a form prescribed and furnished by the division of occupational and professional licenses, for public view in their place of business. All journeymen and specialty journeymen shall have their certificate of competency on their persons or in the immediate vicinity of the work site during working hours. Apprentices and specialty apprentices shall have evidence of registration on their persons or in the immediate vicinity of the work site during working hours.