The 6mm eyepiece offers a wide field of view and superior optical performance at a bargain price. Delivers sharp images with good color correction and contrast. It is Fully Coated for additional light transmission and clarity and the eye relief lets you view the entire field of view comfortably, especially for eyeglass wearers. The 20mm eyepiece is a great choice for general astronomical observation. It is Fully Coated for additional light transmission and clarity and the eye relief lets you view the entire field of view comfortably, especially for eyeglass wearers. All three eyepieces each have their own twist up 2pc Plastic Case for storage.