For 1991-2004 Ford with 4. 6L, 2-Valve, V8 engines; 4.6 4V, 5.4 V8 and 6.8 V10;. Specialty for compressing valve springs and the retainers needed when changing the valve springs. It can also be switched to the rocker arm remover to remove the camshaft, rocker arm and hydraulic lash adjuster.