The Wheelock Eluxa weatherproof series EL3RMT/EL4XMT Multi-Tone Horn and EL4XMTST/EL3RMTST Multi-Tone Horn Strobe (and Amber) appliances are designed for easy installation with a pre-wire capable EL4XBB surface box or EL3RMP mounting plate. Eluxa EL3RMT/EL4XMT Multi-Tone Horn and EL4XMTST/EL3RMTST Multi-Tone Horn Strobe (and Amber) are UL Certified for fire protection service under Standard UL1971 for Signaling Devices for the Deaf and Hard of Hearing, UL1638 for Visual Signaling Devices and Standard UL464 for Audible Signaling Devices. The Eluxa 4X/3R Multi-Tone is also ULC Listed under Standard ULC 526 for Visual Signaling Devices and under Standard ULC-525 for Audible Signaling Devices for Fire Alarm Systems. All Eluxa 4X/3R models are listed for indoor / outdoor use, and for wall or ceiling mount.