Experimental steady-state hysteretic characteristics of ten direct shear seismic damping devices (DSSDs) are presented. The devices were tested over a range of frequencies and displacements chosen as representative of building responses during moderate to severe level earthquakes. Three different damping materials, produced by 3M Corporation and Lord Corporation, were used in the devices. Excitation frequency, strain amplitude, damping material initial temperature, temperature change over the test duration, cyclic energy dissipation, and damping material moduli (including complex shear, storage and loss moduli) are reported for all tests performed. The influence of frequency, displacement amplitude, temperature, and cumulative energy absorption on the damping material mechanical properties and hysteretic stability are examined. Methods by which material moduli can be used to design damping devices for specified spring stiffness and equivalent viscous damping are presented. Limitations of the hysteresis model, test results, and design methodology are discussed.