4EF-5 is a multiband, four-channel infrared detection module. Thermoelectrically cooled photovoltaic multiple junction four-element 2×2 array detector, based on InAsSb heterostructure, is integrated with four-channel transimpedance preamplifier and thermoelectric cooler controller. This module uses four band-pass filters with centre wavelengths: 3.34 µm (CH1), 4.26 µm (CH2), 4.47 µm (CH3) and 4.71 µm (CH4). 4EF-5 is suitable for the detection of common gases.