This iOptron Skyguider Pro Dec adapter from William Optics is a great tool that will give two functions. First, and foremost, the adapter will allow users to attach a Vixen style saddle onto their iOptron Skyguider Pro mount. It can also accept the William Optics Vixen Style Clamp. 

As a bonus, this adapter can act as a riser block. It will raise the dovetail up just a bit and make it easier to focus longer refractors.