The SVBONY fully metal 1.25" Mirrors Diagonal zenith mirror offers an upright figure which is but turned backward in left and right position. It is suitable in particular for astronomical observations. The mirror depicts clean and full of contrasts. The mirror is suitable for refractors, Celestron EQ, Meade Infinity and similar telescopes. It is not suitable due to the length reflectors for Newton. Correct Upside Down Image Correct upside down reversed image easily; wide 90 degree angle makes you view correct image from telescope stand 90 Degree Comfortable Observation It can be used to observe objects with comfortable angle as you observe from above; its convenient to look at the zenith of the sky and close to horizontal observation. SVBONY SV135-This is definitely a must for beginners to start a good eyepiece collection.with this eyepiece, you can enjoy planetary astronomy without spending a lot of money.As a beginner; SV135 is great for starter astronomer! Zoom from low to high power in an instant with SV135 versatile eyepiece Zoom Eyepiece; 7mm-21mm linear continuous zoom; give you more flexibility with out changing eyepieces; Very easy to use and very smooth operation. Blackened lens edges; Anti-reflection threads for maximum contrast; reduce the possibility of the eyepiece slipping out of the focuser or diagonal Barlow Lens Application High magnification for eyepieces to see more details of the moon; bands of Jupiter clearly; SVBONY 1.25" 2x Barlow lens is a better choice. The Barlow lens also could provide more magnification without reducing the exit hole on the eyepiece; it keeps a comfortable observation with wide view. Barlow lens could also provide more magnification without reducing the exit hole on the eyepiece. This barlow allows you to be able to disassemble it, taking off the black lens portion allowing you to add it to other possible configurations.