ZWO T2-1.25″ Filter Adapter

ZWO offers a smart adapter for connecting a 31.75 mm filter to a CCD/CMOS camera while also allowing you to screw the camera onto your instrument.
This solution avoids adding a 31.75 mm nosepiece, which then slides into an adapter or focuser.
Screw-on systems are more secure and less prone to tilting.
The #ZWT2-1.25AD adapter has an external M42x0.75 male thread and an internal M28.5 female thread (the standard for astro filters).