Even though we can’t find CX-411E and CX-411D(-P) in the catalog or website, do you have such products? Also CX-412E and CX-412D(-P).
Yes. The CX-411E is an emitter and CX-411D is a receiver for the thrubeam sensor CX-411. The "P" and "D" marked on the sensor parts are used to help customers in distinguishing between the emitter and receiver components. Regarding thrubeam type sensors, one model number refers to a set of receiver and emitter parts. Just for your information, "P" comes from "Projector" and "D" is from "Detector". These parts are not sold separately.