Alstar 1.25 inch 90-Degree Erecting Prism Optical Inside Rather Than a Mirror which Makes Your Image Clear and Sharp with Eyepiece Adapter Brass Rings for Astronomical Telescope

With this 90-degree erecting prism transform your telescope into a telescope for nature observation with upright and left-right corrected image This is a great diagonal for daytime terrestrial use and night time astronomy applications for telescopes or spotting scopes;filter thread for any 1.25 inch filter and accepts standard 1.25 inch eyepieces The Erecting Prism comes with dust cap and dust plug which prevent dust from entering, for long-time use Constructed from genuine optically processed BK7 glass; this product features a high-quality optical prism instead of a mirror ensuring clear and sharp image quality The prism housing is made of ABS plastic and the barrels are metal for a secure fit; A clamping aluminum screw secures the eyepiece; This allows sideways viewing without the eyepiece falling out