The sE Electronics Reflexion Filter is a portable device for recording live sources with reduced room ambience. It is an advanced composite wall that is positioned behind any microphone by means of a variable position stand clamp assembly which ships with the product. The main function is to help obtain a dry vocal or instrument recording. This is especially useful in studios without proper acoustic treatment, but can also be used to help record takes in control rooms, where the performer also has to operate the recorder, or in rehearsal studios to reduce ambient noise.

The Reflexion Filter also helps prevent any reflected sound from reaching the back and sides of the mic. Its shape and size have been carefully tested to maximize absorption while keeping colouration down to only around 1dB, and leaving the microphone's polar pattern unaffected.