Works as intended - Armasight Hands-Free Night Vision Monocular Kit for Spark / Sirius / Mini-NYX14

It does what it was designed to do, holds the Spark over your left or right eye. In my opinion it is very expensive for what it is but i am not going to build one myself so beggars cant be choosers. I am very happy with how you have quite a few options on which strap to tighten and loosen etc to get the monocular to sit exactly in the right position.