SICK WLG4SP-31312130ZZZ Photoelectric sensors. SICK WLG4SP-31312130ZZZ is a photoelectric sensors in the W4 family. SICK identifies this exact configuration as manufacturer article 1140102. The official technical record specifies Functional principle: Photoelectric retro-reflective sensor; Functional principle detail: Without reflector minimum distance (autocollimation/coaxial optics), ClearSens; Sensing range min.: 0 m; Sensing range max.: 7.1 m; Recommended sensing range for the best performance: 0 m ... 5 m; Light source: PinPoint LED. The linked SICK data sheet is specific to WLG4SP-31312130ZZZ.