A new viscoelaslic model for rubber is presented. It is similar in a Maxwell internal solid model in which all the solids are hyperelastic. A key feature of this model is its ability to accurately predict step-strain relaxation test data for very large strains. A method to obtain the constitutive models for the solids is presented for the three legged version and is used with existing data in the literature to compute variable-rate uniaxial pull tests. The finite-element implementation of this theory is given. Computations are made for a uniaxial constant-strain-rate test using a nearly incompressible axisymmetric version of the finite-element method.