I have two Kowa Prominar 664's that I picked up used and rigged together to form some "Big Eyes". They are in great shape no damage and glass is perfect. The field of view is wider than a Swaro BTX and it may be brighter since there is 120mm of combined glass, but I've not directly compared. I have spotted and Identified sex on deer from 5 Miles out. I made the mounting platform out of a sheet of carbon fiber. The mount is simple and light but does not hold the objectives from moving around, so the scopes have to be shimmed to align the images. It only takes a few seconds once you get the hang of it. Whole package weighs 5lbs 14oz which is a few ounces lighter than the BTX 90. You also, obviously, have the option to break them apart and bring only one on a hunt, or pass one to a buddy.
You can buy both or separately if you like. I don't use them as much as I thought I would. I originally planned on packing them on backcountry hunts, but I'm too much of a weight weenie and changed plans. Just going to stick with my 12x50's. I plan on upgrading my Bino's if I can sell these scopes, but if not I'll put them to work...
Call or Text 805-844-5964
Final Price Drop
single scope- $950 shipped
Both scopes and Mount- $1800 shipped