The SVBONY 5x24 low power;wide angle telescope fixed to the body of a more powerful telescope and pointed in the same direction for initially locating an object to be observed. An adjustable focusing wheel is projected onto a non magnifying viewing window so you can aim the main telescope quickly and easily. High quality eyepieces and objectives. Quality crosshair viewfinder makes targeting celestial objects in your telescope easy! Fully coated, achromatic glass optics yield crisp, bright images for easy aiming. With a brass pressure ring, the SV221 diagonal mirror can protect the eyepiece from being scratched and not damage the service life of the eyepiece. Large screw design. Easy to use, locking eyepiece installation is easier and more stable. The SV221 diagonal mirror has M28.5x0.6mm thread, standard thread size, you can install 1.25 inch filter. The SV221 main mirror shell is made of precision molded ABS plastic, and the lens barrels at both ends are precision machined from aluminum, which will not be easily damaged. Use the SV221 zenith mirror to obtain an upright image and an upside-down image.