We describe the construction of optical scattering cell which has been used for the Brillouin spectroscopy of ferroelastic KH3(SeO3)2. Using a pneumatic transducer, we were able to obtain uniaxial stress up to 18 MPa in a 4 mm cube sample. Temperatures down to liquid N2and up to 60 °C are obtainable with the stability of 2 mK. The cell is constructed for 90 degrees scattering geometry and allows the use of index matching liquid.