The discussion on the use of microwave units specially designed for synthesis use, which are often quite expensive, becomes rather heated at times. Unmodified home microwave units are suitable in some cases. However, simple modifications (for example, a reflux condenser) can heighten the safety factor. High-pressure chemistry should only be carried out in special reactors with a microwave oven specifically designed for this purpose. A further point in favor of using the more expensive apparatus is the question of reproducibility, since only these specialized machines can achieve good field homogeneity, and in some cases can even be directed on the reaction vessel.