The intra-pack vacuum detector is a machine designed to check the correct closure of jars in a vacuum capper while they are being transported on a conveyor. The machine is characterised by its small size, precision and simplicity of operation, and is equipped with a reject system, which significantly facilitates the maintenance of the correctness of the production process. The materials used in the production of the machine are the highest quality acid-resistant steel and polymers dedicated to working in a food environment.