Antares Twist-lock barlows make for easy eyepiece in-out and work with any barrel format. These extend focal length, reduce spherical aberration, extend eye relief and have T2 camera thread with the Twist-lock collar removed. The 1.25"UB1.5STL is a fully multicoated achromat with 27mm aperture and increases the focal length (and eyepiece magnification) by 1.5 times.