The Prototype-5OM assembly described in Volume 1 incorporates new ribcage geometry and chest deflection instrumentation capable of measuring three-dimensional displacements at four critical injury locations on the ribcage. This volume describes the double-gimballed string potentiometer (DGSP) msducer units used to measure ribcage displacements and defines the coordinate systems in which these displacements are described. A FORTRAN computer subprogram called DEFLECT was developed to compute the displacements from the initial positions and output of the DGSP units. Procedures for using this program are described and a listing of the FORTRAN code is provided at the end of the document.