Eliminate the need to make focus adjustments when changing telescope eyepieces.
With parfocal ring equipped telescope eyepieces you can change magnifications quickly and easily.
This set of 2 Alstar Parfocal Rings lets you make a set of non-parfocal 2" telescope eyepieces parfocal for more efficient observing.
The four-lens design with multi-coated surfaces eliminates most of the chromatic aberrations that show up with Barlow lenses having fewer components; A Barlow lens can therefore be a great supplement to your eyepiece collection
The Alstar Barlow lens provides 2.5 times greater magnification; allowing you to observe objects at a significantly closer apparent distance