Teho-Ulvo D-Series
The Teho-Ulvo D-Series contains electronic outdoor warning sirens, produced by the Finnish company Elektro-Arola Oy since 1991. The alarms from the high-power speakers are achieved using a computer-optimized program ("VORO" control software in Finland). Teho-Ulvo D consists of two parts: central unit with control and amplifier electronics and horn speaker set normally installed with a mast pipe. D2400's sound range reaches 1,248 m (4094,8 ft), and the smallest model, D600 reaches 761 m (2496,7 ft). Since circa 2012, the sirens' controllers have been modernized, which resulted in a new sound. The sirens are spread all over Finland in large amounts along with Oy Strömberg Ab, Sarco and German sirens. Teho-Ulvo's have also been installed in Saudi Arabia (amount unknown), with the speakers set significantly more separate.
Models
| Model | Image | Speakers |
|---|---|---|
| D600 | 6-8 (4x2-8) | |
| D1200 | 12-16 (12x2, 16x4) | |
| D1800 | 18-24 (18x6, 24x8) | |
| D2400 | 24 or 32 | |
| D2400/4 MDH | 4 |