Langmuir-Blodgett (LB) troughs are capable of the deposition of multi-molecular LB films onto solid substrates. Typically, these molecular layers consist of amphiphilic molecules such as fatty acids and lipids. Model 611M has a 2 mechanically coupled barriers compressing symmetrically towards the centre of the trough. The dipper and well are also at the centre of the trough. This configuration is ideal if both faces of the substrate are to be coated.