FINEspot® mini photocell EW-1313-0-M
The 3 mm flat sensor in a rugged aluminum housing has a glass protected Fine spot optics. The particularly small opening angle provides a high resolution and a good repeatability. No mutual interference, even in series assembly!

Type: 3 x 13 x 13.5 mm
Range: 500 mm
Resolution :: 0.04 mm (see detail)

Please note that you need a separate amplifier to operate.