Seco-Larm E-931ACC-RC1Q Round Reflector For use with E-931-S33PRQ, E-931-S35RRQ, E-931-S45RRQ Reflective Beam Sensors and E-931CS22RRCQ Entry Alert System For use with E-931-S33PRQ, E-931-S35RRQ, E-931-S45RRQ Reflective Beam Sensors and E-931CS22RRCQ Entry Alert System 3-Inch diameter for improved reflection of IR beam Screws directly into reflector hood