Compress valve springs on overhead valve and L-head engines on cars, trucks and tractors. Tool has a 9-3/4_ throat depth and jaw openings 2-3/4 to 7-3/4_ fits larger engine sizes. Jaws and plunger bar are easily adjusted. Plunger bar seats on both flat- and cup-shaped valve heads. 32 offset and 35 straight jaws are included.