Optec Inc. AP2.7 Knurled Female Threaded Retaining Ring: Extending Industry Standards in Astronomy

• Astro-Physics Industry Standard: Adheres to the AP2.7 inch thread standard, widely recognized and used in the astronomy industry thanks to Astro-Physics' innovation.
• Versatile Extension Tubes: Features female threads on one end and male threads on the other, with knurled bases for ease of attachment and detachment.
• Combination and Stacking Capability: Optec's extensions can be combined and stacked, offering versatility in achieving desired lengths.
• Optimized Spacer Sets: The four and five-piece sets are designed to provide necessary extensions for fixed focal length telescopes in 1/4" (6.35mm) increments.
• Durable Material Construction: Made from high-strength 6061 aluminum alloy, ensuring durability and long-lasting performance.
• Black Anodized Finish: The black anodized coating not only adds to the durability but also enhances the aesthetic appeal.
• Anti-Reflection Features: Includes anti-reflection threading and internal baffles in the largest extension tube to minimize internal reflections.
• Non-Reflecting Internal Surfaces: All internal surfaces are coated with ultra-flat, non-reflecting black paint for optimal optical performance.
• Ideal for Professional Use: An essential tool for professional astronomers and astrophotographers seeking to extend the functionality of their equipment.
• Comprehensive Specifications Resource: Offers detailed specifications and resources for users to make informed decisions about spacer combinations and usage.

Specifications

• Overall Height: 0.10" (2.5mm)
• Outside Diameter: 3.5" (88.9mm)
• Clear Aperture: 2.69" (68 mm)
• Weight: 0.6 oz (15 g)
• Anodize: Gold

• Thread Specification