Williams™ Aperture Twilight 3/8" 1439 are designed to be used on Williams™ Redfield and Lyman receiver sights. The Williams™ Aperture Twilight 3/8" 1439 creates a sharp contrast that gives quick definition to the aperture. It is important to note the following when choosing the correct Aperture for your sight:

Notes:

• The fractional dimension is the outside diameter of the metal aperture.
• The decimal dimension is the size of the hole drilled in the aperture used to aim.
• Twilight apertures are specifically designed for low light situations.