A device for verifying the shade of a patient’s teeth for the fabrication of a dental restorative comprising a mold section and a section for holding a shade tab, both of which are disposed on the shaft or rod of the device. The apparatus includes a spool valve provided in the hydraulic communication path. In this manner, the linear fastener system is capable of providing a precise, secure, and reproducible connection between multiple components without the need to apply rotational torque to the assembly. The concrete for the filling may be pure mineral concrete. The upper layer of mesh material covers an upper opening of the acoustic port.