This Apertura 2X Barlow is different from standard Barlows in one way - it comes with T2 threads on the eyepiece side, which allows you to use the Barlow for photography as well as visually with the help of an eyepiece. Here are your options:

The Apertura 2XB1T Barlow Lens may be used as a typical 2x Barlow in between a 1.25" eyepiece and telescope for increased magnification.

Alternately, you can use the lens element alone by unthreading the chrome barrel and screwing the lens cell into the filter threads of your eyepiece to achieve roughly 1.5X magnification.   This same lens element can also be used with a 1.25" nosepiece to achieve a magnification factor of between 1.5X and 2X with your camera!

Finally, with its versatile T2 (M42x0.75) threads, you can attach this Barlow directly to the T-adapter of your DSLR camera for increased 2.5X magnification. This accessory will connect to any camera that has T2 threads, but the magnification factor will vary, as it depends on the distance between camera's sensor and the Barlow's lens element.