All kinds of detectors can be mounted on the conveyors for checking products for closure, correct position or presence. This can take the form of
a single photocell
a detection bridge with photocells
a detection bridge with switching vanes for physical checking
a label detector
a Dud-detector for vacuum integrity checking
These detectors can be combined via line control with an ejector and a reject table, with stoppers, distributors and other elements in the transport path.