Glass Lenses Set of Six in Wooden Case - 50 mm Dia, 3 Double Convex (20, 30, 50cm FL) and 3 Double Concave (20, 30, 50cm FL) - Eisco Labs industrial and Auto-Power off functions

and Auto-Power off functions

9 relaxing combinations to choose from

the bluetooth earbud provide up to 10 hours hands-free music and calling (depends on volume)

360 Rotation and 180 flip offer you a secure grip

Also this wired binaural headset cover the both ears and helps you to concertrate on the call and hear less ambient noise

Glass Lenses Set of Six in Wooden Case - 50 mm Dia, 3 Double Convex (20, 30, 50cm FL) and 3 Double Concave (20, 30, 50cm FL) - Eisco Labs industrial and Auto-Power off functionsGlass Lenses Set of Six in Wooden Case 50 mm Dia, 3 Double Convex (20, 30, 50cm FL) and 3 Double Concave (20, 30, 50cm FL) Eisco Labs Optics Lens includes 6 lenses. All lenses have been ground, polished faces and ground edges. All lenses are 50mm. TypesOne of each: double convex, plano convex, converging concave convex, diverging concave convex, double concave, plano concave. Lenses are stored in wooden box with hinges and latch to keep lenses