SICK GRSE18S-F233W Photoelectric sensors. SICK GRSE18S-F233W is a photoelectric sensors in the GR18 family. SICK identifies this exact configuration as manufacturer article 1059551. The official technical record specifies Functional principle: Through-beam photoelectric sensor; Dimensions (W x H x D): 18 mm x 18 mm x 38.1 mm; Housing design (light emission): Cylindrical; Thread diameter (housing): M18 x 1; Optical axis: Radial, fully flush; Sensing range max.: 0 m ... 15 m. The linked SICK data sheet is specific to GRSE18S-F233W.