Optex FX-40 Multi-Focus Optics, Spherical Lens Design and superior optical technology provide precise detection capability and durability for unbeatable performance. Optex’s unique sensors satisfy your everyday needs – simplified installation combined with small innovations like easy wire knockouts and invaluable wiring guide convenience. Model: FX-40: standard model featuring Multi-Focus Optics. Model: FX-40D: superior model with additional Double Conductive Shielding