Buyers must prioritize Sound Pressure Level (SPL), typically measured in decibels (dB) at a distance of 1 meter; for high-noise environments, a siren reaching 110-120dB is essential. Additionally, verify the Ingress Protection (IP) rating, where IP65 or higher is required for outdoor or dusty industrial settings to ensure water and dust resistance. The Effective Range should also be calculated based on the ambient noise level of your facility to ensure the signal covers the necessary square footage.