SICK VL18L-4P344 Photoelectric sensors. SICK VL18L-4P344 is a photoelectric sensors in the V18 family. SICK identifies this exact configuration as manufacturer article 6027434. 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 107.7 mm; Housing design (light emission): Cylindrical; Housing length: 107.7 mm; Thread diameter (housing): M18 x 1. The linked SICK data sheet is specific to VL18L-4P344.