The Apertura 2" 2X ED Barlow Lens would be a great addition to any amateur astronomer's accessory case!  The Barlow has a 2" barrel to fit into 2" diagonals or focusers and accepts both 2" and 1.25" eyepieces with the included adapter.  

The doublet lens design of the Apertura 2" Barlow is constructed from one element of high-index glass for unique partial dispersion. The fully broadband-coated glass surfaces offer high-resolution views. Beautifully constructed, the 2" 2X ED Barlow Lens comes with zero height 2" to 1.25" Adapter and 2" internal threads for astronomy filters. Non-marring brass compression rings come standard on the 2" Barlow and the supplied 1.25" eyepiece adapter. This ED Barlow lens provides quality color correction from high-end materials.

Knowledgeable experts agree that the best way to enhance the magnification range of your eyepiece collection is with a 2x Barlow Lens. Overall, this Barlow exudes quality and is a great option for someone looking for a premium 2" 2X ED Barlow Lens. As an added bonus the lens element cell can be unthreaded from the Barlow body and screwed into most 2" eyepieces, for an increase in magnification of 1.3X.