Ergonomically shaped watchmaker's loupe with high comfort . Light duty in newly designed construction and additional viewing port. Pleasant to wear thanks to optimum air circulation through the additional viewing port, and no tarnishing or fogging of the lens more. Screw cap for easy replacement or cleaning the lens. Technical Specifications: Thickness: 3.0 Magnification: 3.3 x Lens diameter: 25 mm Loupe Height: 33 mm Weight: 10 g