this invention relates to an improved injector / valve combination which permits nearly immediate response time to an actuator signal . such a combination is particularly suited for injecting colorants into polyurethane slabstock foam and permits a substantial reduction in foam waste due to low colorations during an on / off cycle . specifically , this invention combination comprises a novel ball valve which allows for instantaneous shut - off and - on without appreciable leakage or pressure drop and without the need to utilize a high throughput flow rate . such a ball valve is used in combination with an injector which is actually attached to the valve , the configuration which permits continuous use and instantaneous on / off without a deleterious pressure drop and minimizes the possibility of turbulence as the liquid polymeric colorant flows through the injector . the ball valve , the attached injector configuration , the coloring apparatus comprising the inventive ball valve and / or the attached injector configuration , and the slabstock foam colored through the utilization of such an apparatus are also contemplated within this invention .