SICK WTB9-3P2281 Photoelectric sensors. SICK WTB9-3P2281 is a photoelectric sensors in the W9 family. SICK identifies this exact configuration as manufacturer article 1094676. The official technical record specifies Functional principle: Photoelectric proximity sensor; Functional principle detail: Background suppression; Dimensions (W x H x D): 12.2 mm x 49.8 mm x 23.6 mm; Housing design (light emission): Rectangular; Mounting hole: M3; Sensing range max.: 20 mm ... 200 mm 1). The linked SICK data sheet is specific to WTB9-3P2281.