Siemens Sirius Series Siren, 24 V ac/dc, 30 mA, IP65

Make some noise with this 102dB siren from Siemens. It has eight tones to choose from and adjustable volume, so you can set it up to warn your people as soon as a hazard occurs. The device is quick to install using the secure bayonet mechanism, which also enables easy replacement of the acoustic elements. An expected service life of 5000h makes it a long-term alert system that you can use anywhere from factory floors to laboratories. This siren is part of a modular system that also allows you to install a continuous light, flashlight, blink lights and rotating lights.

• IP65 rating means it's dustproof and protected from water spray
• Broad operating temperature range of -20°C to +50°C makes it suitable for harsh industrial environments
• Compact dimensions of 70 (W) x 54mm (D) allow it to fit in tight spaces

Both. You can power it with an AC supply such as the UK mains (stepped down to 24V AC), or a DC supply that's used in many industrial settings.