Rigel 2" Ultra Wide Angle Eyepiece.

SUPERIOR OPTICS
Ultra wide angle 80 degrees, high quality fully multicoated glass. Super sharp, high contrast & excellent aberration correction, extremely high resolution. Fold-down rubber eyecups, filter threads, blackened lens edges, anti-reflection threads for maximum contrast, upper barrels are black anodized aluminum with a rubber grip ring.

• Focal length: 15mm
  
• AFOV: 80 degree ultra wide angle
  
• 6 ELEMENTS / 4 GROUPS

• Focal length: 20mm
  
• AFVO: 80 degree ultra wide angle
  
• 7 ELEMENTS / 4 GROUPS

• Focal length: 30mm
  
• AFOV:80 degree ultra wide angle
  
• 5 ELEMENTS / 3 GROUPS
  
• 22MM EYE RELIEF

Works well with refractors and scopes f/5 and slower.