This SICK HTB18-P4A2BB Photoelectric Sensor, MPN 1073431

Specs:

 Functional principle Photoelectric proximity sensor
 Functional principle detail Background suppression
 Dimensions (W x H x D) 16.2 mm x 48.5 mm x 31.8 mm
 Housing design (light emission) Hybrid
 Thread diameter (housing) M18
 Mounting system type M18, head/side (24.1 … 25.4 mm)
 Housing color Blue
 Sensing range max. 5 mm ... 300 mm 1)
 Sensing range 5 mm ... 150 mm 2)
 Type of light Visible red light
 Light source PinPoint LED 3)
 Light spot size (distance) 7 mm (300 mm)
 Wave length 631 nm
 Adjustment
 Potentiometer, right Sensing range
 Potentiometer, left None
 Special features Signal strength light bar