SICK ZLD18-4FZ4A8 Photoelectric sensors. SICK ZLD18-4FZ4A8 is a photoelectric sensors in the Z18 Simple Sense family. SICK identifies this exact configuration as manufacturer article 1099298. 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): 13.6 mm x 44.2 mm x 33.3 mm; Housing design (light emission): Hybrid; Thread diameter (housing): M18; Mounting system type: M18, head/M18, base. The linked SICK data sheet is specific to ZLD18-4FZ4A8.