It can adjust the eyepiece position; helping you get a clearer image. Applications: Supports all types of telescopes, reflectors, refractors to observe star clusters, the Moon, planets and other celestial bodies. All metal, no glue needed, no formaldehyde, environmentally friendly, no need to stick. The metal ring thread is screwed on directly. No glue is needed. It will never come off. It 't fall off or debond over time. No black glued pressing ring. You need to measure the outer diameter of the telescope objective lens to select, you cannot choose according to the diameter, for example: 127SLT outer diameter 146mm - suitable for 160 solar film, 8SE outer diameter 235 - suitable for 250 solar film. Type:80mm Colour:As Shown Material:Metal Package Contents: 1 * Composite membrane filter Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.