Optex FX-360 is an extremely cost effective 360 degree ceiling mount detector. It provides the most unbeatable detection performance and reliability in its class. The FX-360s sleek and compact design suits all types of installation applications. Features: Ceiling Mount with Unparalleled 360 degree Detection Performance. Originally Designed Hard Spherical Lens. RFI Immunity 20V-m. Patented Multi-Focus Lens. Selectable Pulse Count : 2 or 4. LED On-Off Switch. Tamper Switch. Improved EMI