The IRP-EC is opaque to block out outside noise and interference (signals). It also helps concentrate the IR signal from the emitter to the device front IR sensor. Use with every install that does not require IR pass-through to end the saga of emitters falling . No more truck rolls for the professional and frustration for the home enthusiast They also fit Calrad, NextGen, Global Caché, Sewell, TNP, Betige, and other IR emitters of similar size. All mentioned companies are the trademarked rightful owners