This is a 12-leaf front spring pack for a K5 Blazer. The springs have a ton of travel (so much that our 14-inch-stroke shocks are too short). But the spring rate was too soft, and even though the truck was floating at the right height, the front end would bob too much. We had National add another leaf into the pack to stiffen up the front end a bit. Be careful though, as many times bobbing can be due to improper shock valving, so be sure you're addressing the correct problem.