Wilson produced many lesser-known models with the Pro Staff mold, including the Jack Kramer Pro Staff 85 (80% graphite and 20% fiberglass), the Matrix, the Graphite Cruncher, the Graphite Aggressor, the Ceramic, and several others. These variants were less stiff than the well-known graphite/Kevlar model. Chris Evert used the Jack Kramer model to reach the final of the 1984 French Open, in which she was defeated in straight sets by Martina Navratilova, who was using the Yonex R-27, a graphite/boron design similar to the Ultra II. She defeated Navratilova in 1985 with the graphite/Kevlar Pro Staff 85. Navratilova, meanwhile, had switched back to the less stiff R-22, a graphite/fiberglass model.