- Holds sensor pairs in the opposite arms of a rugged U-shaped housing
- Available with 10 mm (SL10) or 30 mm (SL30 and SLO30) slot widths
- Responds in 1 millisecond or 300 microseconds, depending on model
- Uses visible red (SL10 and SL30) or infrared (SLO30) beam
- Features 4-turn potentiometer senstivity adjustment (SL10 and SL30)