Bought to either fit guidescope or refractor on top of SCT and slide along long vixen rail to help with balancing when necessary. Works well and is very secure.

I bought this to allow me to move a Guidescope (Skywatcher 50ED) back and forth on an extra Vixen bar on my Edge 8HD to help achieve balance (in particular with and without Hyperstar attached). Does the job perfectly, nice and solid, and large tighteners. Albeit - I have a cut in half squash ball to help untighten these as they pretty solid when tight.