Yukon scope (by Sibir, made in Russia) has huge 50mm rear glass, offers adjustable 20x to 50x magnification. Has mounts for the two common tripod bolt sizes, but can be hand-held. Monocular/scope, not binoculars. Note: this is for distance use; if you just use it for watching birds in your back-yard, you'll find that you can't be far enough away to focus properly.