This 1953 Chevy backup lamp lens is a reproduction of the original GM lens, clear in color. The 1953 Chevy has 3 lenses as part of the taillight assembly. Those 3 lenses being an upper red lens, center red lens and lower clear lens which is the backup light lens. They are made of plastic. There is a 4th lens involved in the 1953 Taillight Assembly. That lens is the inner flat lens found inside of the upper red lens. The lens defuses or spreads out the light when the red brake are applied.
One important point to understand in reference to 1953 versus 1954 Chevy Taillights. The rear fender area on the 1953 or 1954 Chevy where the taillight mounts is the same for both years. But the backing plate that the chrome bezel mounts on, is different on the 1953 and the 1954 Chevy. So to change the taillight assembly from 1953 to 1954 you need to replace all the lenses, chrome bezel and the backing plate.