I had a hard time with this item. It's difficult to impossible to get good focus. It made me nauseous just looking through it. To try to focus, you are back and forth with the two adjusters. The distance doesn't seem right for what it purports to be either.
This Waterproof & Dual Focus Monocular lists for $40.00. But, it sells for $17.99. The links to buy are below.
Vital Link: Amazon