SICK VL18-4N3140V Photoelectric retro-reflective sensor. SICK VL18-4N3140V is a archive in the V18 family. SICK identifies this exact configuration as manufacturer article 6035496. The official technical record specifies Functional principle: Photoelectric retro-reflective sensor; Functional principle detail: With minimum distance to reflector (dual lens system); Dimensions (W x H x D): 18 mm x 18 mm x 83 mm; Housing design (light emission): Cylindrical; Housing length: 83 mm; Thread diameter (housing): M18 x 1. The linked SICK data sheet is specific to VL18-4N3140V.