I have one for the iphone 6 and my Swarovski ATX spotter. It's a little pricey at $85 shipped, yet I never found any substitutes besides the Swarovski brand adapter phone case. But, Swaro only makes it for the iphone 5 at this time and it is twice the price. So PhoneSkope won my money.
Very glad I purchased this adapter because it serves it's purpose amazingly. I'm finally able to take remarkable pictures with my phone through my spotting scope; every time. No more taking a thousand snaps to get one barely decent pic of a deer with its head turned in the wrong direction if I'm lucky.
I will give you my qualms about the phoneskope though. It is extremely rigid and tough for taking on and off regularly. In fact, it fits so tight on my phone that the clear lens protector I put over my screen peeled off. With the phoneskope obviously being a device that is going to be taken on and off the phone regularly I think the design could have been just a tiny bit more loose and forgiving when taking it on and off the phone. The upside to this is that it is a very sturdy piece. It actually looks like billet plastic that was carved form one piece. You can literally see some machining marks. There are mold marks too where pieces must have been sandwiched and plastic welded together. But all in all this is a very strong part. Almost too strong for it's intended use though.