A flip kit is a lowering kit for trucks that allows the suspension to be lowered by flipping the axle. The most common use for a flip kit is to lower the truck so that it can be used as a daily driver, but it can also be used to lower the truck for other purposes such as off-roading or show. A flip kit will typically lower your truck by 2-4 inches, but this will vary depending on the brand and model of kit you choose.