The OPTEC-4300 25mm Extension Ring provides approximately 1-inch of extension for any OPTEC-4300 telescope adapter. Ideal for telescopes where the Gemini Focusing Rotator may need to pushed out and away from the OTA to provide clearance for cooling fans or when a little extension is required to reach optimal focus.

Specifications

• Any OPTEC-4300 telescope adapter.
• Gemini Focusing Rotator.
• TCF-Lynx3 3-inch Focuser.
• Inside Diameter: 3.9" (99mm)
• Outside Diameter: 4.95" (126mm)
• Overall Height: 1.30" (33.2mm)
• Clear Aperture: 3.9" (99mm)
• Weight: 8.8 oz (250 g)
• Back-Focus Usage: 0.984" (25mm)