The QuantiCheck is the first quantitative respirator user seal check device. The user engages the QuantiCheck, takes a comfortable breath and holds. At the lowest point of the negative pull, the system starts a calculation which is a proprietary algorithm that measures pressure loss from the respirator. The system simply indicates that the weakest point will be the required air entry point into the mask. The system is a static user seal check indicating the fit of the mask at the point in time the system is used.