Power Roar EMP-355S high-efficiency Class D megaphone offers extended 8 hours battery life and durable construction for guaranteed reliability. A powerful choice for outdoor use, this robust megaphone is designed to last for years of enthusiastic use. 1.Class D High-efficiency megaphone offers extended battery life. 2.Ultra light-weight and durable construction for guaranteed reliability. 3.Broadcasts up to 450m for any public event setting.