Bruel & Kjaer HATS 4128C BRUEL & KJAER Head & Torso Simulator (HATS) 4128C Head & Torso Simulator Types 4128C & D are manikins with built-in mouth simulators and calibrated ear simulator (according to IEC 60318-4 and ITU-T Rec. P57 Type 3.3) that provide realistic reproduction of the acoustic properties of an average adult human head and torso. They are ideal for performing in situ electroacous..