SICK WTB4FA-31311120ZZZ Photoelectric proximity sensor. SICK WTB4FA-31311120ZZZ is a archive in the W4 family. SICK identifies this exact configuration as manufacturer article 1126169. The official technical record specifies Functional principle: Photoelectric proximity sensor; Functional principle detail: Background suppression, LineSpot technology; Sensing range min.: 7 mm; Sensing range max.: 150 mm; Adjustable switching threshold for background suppression: 15 mm ... 150 mm; Reference object: Object with 90% remission factor (complies with standard white according to DIN 5033). The linked SICK data sheet is specific to WTB4FA-31311120ZZZ.