Abstract: A fire sprinkler valve trigger has a body or capsule segmented into opposite segments joined together at a joint by a fusible material with a predetermined and selected melting temperature less than a melting temperature of the opposite segments. An exterior of the body or capsule comprises a layer added to the exterior, and comprising a preselected color corresponding to and designating the melting temperature of the fusible material. The body or capsule, including the joint and the fusible material, being exposed and visible so that the layer on the exterior of the body or capsule is exposed and visible.