| Real Tube Manufacturer | Mullard |
|---|---|
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|
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| Country | Great Britain |
| Etched code on Tube | 1593 E3, 1593 F3 |
| Factory Code | B - Mullard, Blackburn |
| Year | 1953 |
| Tip Shape | Pinched Tip |
| Glass Color | Clear Glass |
| Mica | Double |
| Getter | Square Getter |
| Getter Support | Double |
| Plate Look | Ribbed / Scale |
| Plate Size | 17mm |
| Plate Color | Matte Gray |
| Pin Color | Silver Pins |
| Special Use | KB - UK Military |
| Other Marks | Vertical Code |
