Clear tubular. Quarz burner. High efficiency. Working with external ballast and ignitor. Pulse Ignitor specifics: nominal frequency 50- 60Hz. Ignition voltage: 3.5 ÷ 5.0kV. Supply voltage: 220 ÷ 250V 50-60Hz for appropriately rated series choke ballast; sup plies outside this range require a transformer to ensure correct lamp operation. 250W - 400W: equires anti-shattering and anti-UV shield. Minimum starting temperature: -15°C. Anti-UV shield is suggested when illuminating light sensitive materials.