Opaque styrene cassette housings are in opaque brown color to prevent transmission of light into the cassette.
| Model No. | Diameter (mm) | Type | Style | Qty / box |
| CHOP237-50 | 37 | 2-Piece | Standard Style Opaque Styrene | 50 |
| CHOP337-50 | 37 | 3-Piece | Standard Style Opaque Styrene | 50 |
