Quality used can vacuum testing unit to be installed in-line production lines. It has a simple operating principle for the elimination of defective cans (pin holes, dented flanges, cracked flanges, cracked welds, etc.). Standard vacuum degree is applied to cans and those found faulty will be automatically rejected. The infeed belt with screw feeds cans to the rotary testing unit with 40 heads. As each head completes a full revolution, it depressurizes the can being tested to a standard pressure value. Any variations detected in this depressurization mean there is a leak in the can, so the machine produces an electronic signal or ejects the can.