The 42mm ring is great and fit my boy's 15x56 vortex diamondback HD binnos perfect. I like that it is aluminum, lightweight and durable. My only complaint is that the 42mm ring appeared to be used. The felt inside the ring was peeled off in areas leaving it gooey and other spots the felt was worn down or gone.
It works "okay" but there are obvious improvements that could be made. Like instead of a screw on mount, use a bayonet mount so you can leave the adapter ring on the scope. Simple. Also, provide a lens cap for the adapter so if/when you do leave it on the scope, you can put a cap over the ocular lens. I emailed Outdoorsman's and they pretty much blew me off. Also wouldn't even tell me the thread pitch (gave me some "proprietary" bs) so I could search for a cap for the adapter. The adapter and phone case are well made, like most Outdoorsman's stuff, but also very overpriced - again, like most Outdoorsman's stuff. When I saw this product I thought it would be a lot better than the PhoneSkope system I was using. In some ways it is, but in other ways it isn't. I'd say it's a wash really. Not sure I'm glad I switched.