SV135 eyepiece is a good assistant for you to observe and take pictures of the planets. More comfortable to view the moon, Jupiter and Saturn. 36°-52° field of view. This is a zoom eyepiece considering that it zooms from 7mm to 21mm. which allows you to see different wide field of view under the same viewing conditions. Meet your different needs. Provide comfortable observation experience. 13-14mm wide eye relief can also provide an easy and pleasant viewing experience. It is also friendly to people wearing glasses. 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.