Product Size: UHC filter, diameter 3.18cm/1.25inch.Durable Material: The telescope filter is made of high quality optical glass and aluminum frame, wear resistant and durable to use.Astrophotography Accessory: The UHC filter is a broadband filter in the astronomical filter series, it is used to improve the contrast of the image, decrease the effect of the city light pollution, and make the astronomy observation clearer.Easy to Use: high contrast filter with British thread standard, directly attach the filter to the astronomical telescope with a 1.25" eyepiece. Wide Applications: Professional astronomical telescope filter, helps deliver clear images, perfect for astrophotographers and astrophotography. Specification: Material: optical glass aluminum Package Includes: 1UHC Filter Note: Please allow slightly errors due to manual measurement and different monitors.