Optex / Morse - AX-100TF - 100' Outdoor 4 Channel Select Dual Beam Weatherproof housing keeps water, insects and dirt out Fully adjustable to meet your application Anti-frost convex visor design protects from effect of frost and dew Environmental disqualification circuit helps eliminate false alarms from birds, falling leaves, etc. Selectable beam frequencies to avoid unwanted crosstalk when using multiple units