When observing with a CCD camera, it is common probem getting a filter between the telescope and camera, but there is no suitable thread anywhere. Therefore, I do offer the inlay-ring with internal M28,5x0.5 thread to insert it anywhere between M42/T2 spacers or adapters, telescope, or camera.
With the inlay ring you can fit a 1,25" filter in almost any location in the beam of light.
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