The OPTEC-4300 12.5mm Extension Ring provides approximately 1/2-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.

Compatible With 

• Any OPTEC-4300 telescope adapter.
• Gemini Focusing Rotator.
• TCF-Lynx3 3-inch Focuser.

Specifications

• Inside Diameter: 3.9" (99mm)
• Outside Diameter: 4.95" (126mm)
• Overall Height: 0.81" (20.6mm)
• Clear Aperture: 3.9" (99mm)
• Weight: 5.0 oz (145 g)
• Back-Focus Usage: 0.492" (12.5mm)
• Drawing