66 degree perfects for broad field lunar observations;medium sized star clusters;wide range of cloudy nebula's and deep sky targets with extra sharpness. Eyepiece Series: Ultra Wide Focal Length: 6mm,9mm,15mm,20mm Barrel Size: 1.25" (31.7mm) Apparent Field of View: 66° Filter Threads: Standard 1.25" Filter Thread (M25.8*0.6) Eye Relief: 15mm Coating: Fully Multi-Coated Black end lens Edges: Yes Rubber Eye Guard: Yes Color: Black Net Weight: 93g Height: 3.0" (77mm) Quoted price is per eyepiece rate..