These superior quality unmounted Double Concave Lenses with ground edges are useful for teaching a variety of optical principles.
| Order# | Description |
| 7-909-8 | 38mm d. x 10 cm. F.L. |
| 7-909-9 | 38mm d. x 15 cm. F.L |
| 7-909-10 | 38mm d. x 20 cm. F.L. |
| 7-909-11 | 50mm d. x 20 cm. F.L. |
| 7-909-21 | 50mm d. x 10 cm. F.L. |
| 7-909-22 | 50mm d. x 15 cm. F.L. |
| 7-909-12 | 75mm d. x 20 cm. F.L. |
Double Concave Lenses have two inwardly curved surfaces, a negative focal length, and are often used to aid in the distribution of light as well as image reduction.
