Specifications include, but are not limited to: A.2.3 Cabinets and Enclosures: The batteries, charge controller, and sign controller must be housed in weatherproof enclosures. The enclosures must be lockable by an ODOT provided padlock to prevent the access of unauthorized personnel. A.2.4 Ventilation: The sign must come with ventilation to minimize condensation and heat dissipation. A.2.5 Labels: All major components and wiring must be individually labeled by a permanent means. Advertising is not allowed on the sign except for the standard markings normally on a unit. A Contractor’s identification sticker, not to exceed four (4) by six (6) inches, may be applied. A.2.6 Viewing Angle: The angle at which the luminous intensity of the LED is one-half the intensity at the optical axis must not be less than 15 degrees, so that the minimum total viewing angle is 30 degrees centered about the optical axis. A.2.7 Display Technology: The sign must be constructed using light emitting diodes (LED’s) only. The LED’s shall be capable of displaying the color amber, 590 nm (nominal). LED color and intensity shall be distributed uniformly throughout the sign and shall be consistent from pixel to pixel. A.2.8 Visibility and Legibility: The sign must be visible from one half mile under both day and night conditions. The sign’s message must be legible from a minimum distance of 650 feet as required by the MUTCD. The sign must have at least one photocell to measure the ambient lighting conditions and automatically adjust the LED’s brightness to maintain legibility. A.2.9 Characters: Each character must be defined by a NEMA TS-4 5x7 matrix font. The signs must be capable of displaying all upper case letters and all digits. Characters must use the complete height of the matrix.